 Chapter 0 of The Ocean of Air – Meteorology for Beginners This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. The Ocean of Air – Meteorology for Beginners by Agnes Jubin, Preface by Reverend C. Pritchard, and Authors Preface. In the year 1879, the proof sheets of a little work entitled Sun, Moon, and Stars, now happily well known, were placed in my hands by a friend who asked me to give a passing glance over their contents. The work appeared to me to be so excellent of its kind, and gave, as I thought, so much promise of public usefulness that I volunteered gratuitously the offer of a preface, if it were thought that I might thereby contribute to its wider circulation among the intellectual and educated classes, whether older or younger in years. Since then I have been gratified by the fulfillment of this vatestination in the recent appearance of a thirteenth edition, and I think it will be for the public advantage if it shall be even more extensively read. A few weeks ago, the same authorists sent me the revised proof of the present work on the varied and wonderful properties of the Ocean of Air, which surrounds our earth, and requested my opinion on the execution and value of the contents. I confess, at first thought, I considered that so extensive and complex a subject required an amount of study and of accurate information which could hardly be expected from an unprofessional author. It would, as it seemed to me, tax the cultivated powers even of Sir John Herschel, and, if successfully executed, might take its place alongside his remarkable, familiar lectures. After an hour's cursory perusal, I found myself enchained by the multitude of pleasant thoughts suggested by the description of the physical circumstances surrounded by an immersed in which we pass our being, expressed moreover in a language at once so graphic and so simple that I offered for the second time to exert any influence which I might possess in the recommendation of the book to the general notice of educated persons. The points touched upon in the course of the work are very multi-form, embracing the greater part of the natural phenomena familiar to us in our daily experience. Heat and cold, the calm and the storm, thunder and lightning, vapor and cloud, rain and dew, the passage of light and of sound, each and all of them in their turns receive their share of illustration in the most pleasant of literary styles. Nor does the authorist hesitate to encounter the marvelous conflicts of the molecules constituting the phenomena of atmospheric pressure and of heat and light, while in due course she extends her flight to the regions of the aurora and of the meteoric dust there floating and luminous, then gradually falling on the earth and on the wide surface of the ocean and ultimately dredged up in the form of mineral nodules from the remotest depths of the Pacific. A pleasant diversion is then made to the flight of the birds of the air and to the locusts which are driven onwards by its winds. It is by a fascination of this sort that the reader is almost unconsciously to himself led to a general conception of the plan and the forces of that part of the course of nature amidst which he draws his breath and lives. There are more aspects than one in which a little work like the present may be intrinsically valuable and in which that value reaches to young and old alike. As to the young it cannot fail to excite those facilities of curiosity and imagination which when restricted to their proper sphere are among the most valuable of our natural endowments. In most cases it will probably satisfy the curiosity which it excites. In respect of those who are of an older growth it must not be forgotten that though most of us are not called upon to become philosophers or experts, still we can, all of us, if we choose, obtain a general and intelligent conception of the nature of the phenomena in the midst of which we live and move and have our being. The amount and the intrinsic accuracy of our conceptions of these phenomena need not be great for the ordinary purposes of life, but to remain willfully and purposely ignorant of their existence and their meaning is hardly worthy of beings who rank themselves among the rational orders of the creation. It will also be found, I think, that very many of our mental enjoyment spring from a knowledge which is far from complete or profound and that the most pleasant of them are associated with a knowledge which is comparatively superficial. It is in the by-place, the peregra of the intellect that the better part of the intellectual enjoyment is found. It is in this direction, I think, that we are to look for the chief recommendations of the little book before us. Beyond this a casual remark here and there will probably touch cords within the mind which once so touched will never cease to vibrate and lead to trains of thought and occupation at once harmonious and beneficent. In this way a few specks of dust swept up from the hearth and placed under a modern microscope have revealed to the instructed eye the wonders of a tropical jungle and the formation of coal fields therefrom, and thereby have fired the mind with a passionate desire for more extended knowledge of the primeval formations of our globe and of the structure of the grasses which once have clothed them. It is trifles and accidents such as these which not rarely have determined the whole bent and aim of an intellectual life. Lastly, I think there is another aspect under which this unpretending little book may possess a considerable value and it is this. The education at our great public schools and even our universities is yearly becoming more technical and is falling more and more under the dominion of cram and of the schedule and of the syllabus and of the examiner. The schoolboy is fast becoming hot pressed. He is urged by considerations which he cannot resist to maintain or extend the credit of his school either by conventional distinction in Greek or Latin or in what is miscalled natural science or if he be hopeless in these directions he must at all events contribute to its fame by athletic feats. Thus his young life is marked out for him and trampled within narrow limits while the actual bent of his mind and the true reach of his natural capacity become ignored or unsatisfied. In the pommy days of the old school life the boy who made but a poor figure in his form might be take himself to collecting butterflies or beetles or to keeping mice and dissecting them when dead. In this way the foundations might be laid for pursuits in life leading to eminence and usefulness. As things are his natural curiosity too often is stifled that forward looking faculty his imagination becomes atrophied and his mental endowments molded into a stereotype. From my professional position at the university it is my misfortune to observe and deplore a very large and mischievous amount of this suppression of curiosity and a general absence of a knowledge and love of nature which I take to be the necessary consequence of the modern style of education when pushed as it often is to an extreme. I cannot doubt but that the eminent and highly cultured scholars who adorn the headships of our noble public schools perceive and deplore this result of a system which through the varied pressures of social life they are at present unable to control. It is here that I think this little volume with its multitudinous and interesting peeps into the nature of the things around us may become signally useful. If I had now the opportunity which I once had I would place Miss Gibairn's little volume in the hands of the boys in the upper forms of the school and encourage them to read it as an amusement and for a change of pursuit under the hope that the pleasant and varied information it contains might find a response and a home not reachable by the ordinary routine of school life. What I have here indicated as serviceable for boys is at least equally so for the other sex nor as I have already said do I think its interest or utility is limited to the years of our youth seeing that it was not without a species of fascination that I read it myself. It is indeed but a little book but it treats of many objects and many phenomena of constant occurrence and it possesses the great advantage that it can be taken up and laid down again piecemeal and it fragments of time. Bread thus cast upon the waters will be found hereafter in an abundant harvest of pleasant association for hours of contemplation or of leisure. After the generous words of Dr. Pritchard about my little book there is small need for me to say much. First and foremost I must express my hearty gratitude not only for the warm praise which he has accorded but also for the infinite trouble which he has taken in reading the revise pointing out some weaknesses and here and there suggesting improvements. I can never forget what I owe to his kindness both with this book and with Sun, Moon and Stars. In writing The Oceans of Air I have had a wish to make it one of a trio of volumes. It may be said to occupy a position between my two earlier scientific books Sun, Moon and Stars had for its subject the vast realms of space dotted with Suns and Worlds. The Worlds Foundations had for its subject the crust of our Earth and the story of the crust formation. The Oceans of Air has for its subject the expanse dividing the two, that broad belt of atmosphere which rests upon the Earth's crust and reaches upward to surrounding space. I might end with a catalog of books and cyclopedias to which I have had recourse for information, but many of them are referred to in the following pages and the entire list would be cumbersly long, so I will only close with a word of particular acknowledgement to the authors of any extracts which I have ventured to make without writing to ask express leave. I trust that in such cases the emissions will be pardoned. Wharton House, Eastburn, October 1889. End of Chapter 0 Chapter 1 of The Ocean of Air Meteorology for Beginners This is a LibriVox recording. All LibriVox recordings are in the public domain, for more information or to volunteer, please visit LibriVox.org. The Ocean of Air Meteorology for Beginners by Agnes Giban, the air in which we live. Our Earth has many robes, closely fitting garments come first of brown soil or gray rock and green grass, with wide liquid underskirts of deep blue filling up the spaces between. Outside these coverings, more wonderful still, fragile yet strong, transparent, almost invisible, folded around layer upon layer, or as one might say, veil upon veil, each more gossamer-like than the last. These form Earth's surrounding atmosphere, a substance pervading everything, found everywhere. One may travel from the equator to the poles, one may journey by sea or by land, one may soar high in a balloon or descend deep into a mine, but one can never, in this world, go to a place where the atmosphere is not. A substance, for air can be felt, air has weight, air occupies space, air, like any other body, can be made hot or cold, air is composed of particles of substantial matter. A child, not to speak of a grown-up person, opening a box which holds only air will naturally say, nothing here, but something is there, something very definite and real and of no small possibilities. Those same quiet air particles, actually unfelt by the hand moving gently among them, have strength, when stirred into a hurricane blast to uproot huge trees, to sweep away vast buildings, to raise ocean waves upon which mighty ships are tossed helplessly about, like eggs in a boiling cauldron. Air may be felt, the faintest breeze cannot stir without a man becoming conscious of the air particle striking against his face. He cannot ride or run through the air without the same sensation. If he even moves his hand quickly enough to and fro, he is aware of something resisting his hand. Air can be made hot or cold, we all know from experience the difference in our feelings when cold air particles on a frosty winter's day or hot air particles on a sultry summer's day strike against our bodies, either giving over to us of their heat or stealing away some heat from us. Air also has weight and occupies a certain amount of room, just as a massive iron or of lead weighs so much, a massive air has its own particular weight. This means that air, like iron or lead, is subject to earth's attraction, which is only tantamount to saying again that air is a substance. Nothing which is not a substance can possibly be attracted by a substance. If air is a substance, it must occupy space, it must take up room. It may be very light, very slight, very elastic, and very compressible. Other bodies may pass easily among the air particles, pushing them apart, or squeezing them closer together. Yet space it must have. Air, being distinctly a something, has to be somewhere. Air has a faint bluish tint, which on a sunshiny day becomes in the sky a very pure and deep blue. This tint is not believed to be the natural color of the atmosphere. Were it so, the air would merely act the part of a blue pane of glass, rendering the white light of the sun blue as it reached our eyes. But the blue of the atmosphere is known to be a reflected blue. If reflected, there must be something in the atmosphere to reflect it, and such indeed is the case. Perfectly pure air would doubtless be without color, but perfectly pure air we do not find. The whole atmosphere is full of multitudinous, minute specks, so small as to be in themselves invisible, so light as to remain aloft. To the presence of these, the blue tint is believed to be dew. They scatter the light of the sun and produce the blue effect. A beam of strong white light caused to pass through a liquid, which contains a large supply of minute floating particles is affected by them in a like manner. The short blue waves are more abundantly reflected than the long red waves, and so the water seems to be blue. This explanation serves for the deep blue color of the ocean, as well as for the blue of the atmosphere. The whole earth is surrounded by this marvelous air ocean, an ocean of gaseous matter, at least 100 times as deep as the water ocean. At the bottom of the gaseous ocean, we small human creatures crawl about commonly on flat, lower levels, the ocean bottom in fact. Sometimes, with much toil and trouble, we climb the little ridges and mounds, called mountains, little compared with the depth of the atmosphere, though not little compared with ourselves. The highest mountain peaks of even the vast Himalayas lie low down near the bottom of the ocean of air. Our position is, on a bigger scale, much the same as that of the crabs and crayfishes crawling laboriously about at the bottom of the seawater tanks in the Brighton Aquarium. Only they are in a minute world of water, and we are in the large world of air. They have over their heads only a few feet of the fluid in which they live. We have over our heads many miles of the fluid in which we live. Authors note, air and water are both fluids, though different in kind. Also, it seems probable that they cannot see beyond their confined regions of water, while we have eyesight which can pierce far beyond our wide regions of air. But the very extent of the ocean of air adds to our difficulty in studying its nature. All observations that we can make must be limited by the state of the atmosphere just around ourselves. We can never get out of and beyond the atmosphere so as to see it as a whole. At any time, a slight local fog is enough to put a stop all together to such observations, beyond the unpleasant experience of the fog itself. Just so a crab, wishing to study the general condition of the water in his tank from one corner of it, would be hampered by the stirring up of a little mud or sand in his own neighborhood. In all study of the Earth's airy envelope, we have to allow for these difficulties to confess ourselves apt to and not to dogmatize hastily upon questions about which we are not well informed. We can never in this life get beyond the ocean of air, for man and beast cannot live without air. To breathe means life. To cease breathing means death. That which we breathe is the air around us, the ocean of almost invisible gases. It used to be supposed that the atmosphere reached only to a height of about 50 miles above the Earth's surface. We are driven here to conjecture to some reasoning from certain tokens and perhaps to a good deal of guessing. Being always imprisoned at the bottom of our oceans, we cannot measure for ourselves how far it extends above. Of late years, the opinion has gained ground that the atmosphere reaches to a height certainly of two or three hundred miles, probably four or five hundred, possibly a good deal more. But the condition of the air far above is different from that of the air in lower levels where we live and breathe. The higher we ascend, the more thin or rare becomes the air. A less quantity fills a certain space up there than down here. The particles float farther apart from one another. This difference in the density of the air is chiefly due to attraction. Each separate air particle is drawn steadily earthward by the force of gravitation, and that force is stronger on the surface of the earth than at a distance. The closer to the earth, the heavier the pull. The farther from the earth, the less the pull. Besides the actual attraction of the earth drawing the air particles downward, there is the great weight of the whole atmosphere above caused by the same attraction. Miles and miles of air overhead press mightily downward, packing tightly together the lower layers of air near the earth's surface. If thousands of bales of cotton wool were piled into an enormous heap, the upper layers might be light and loose in their make, but the lower ones would be squeezed into a very small compass by the pressure of the mass above. Without this pressure of the overlying atmosphere, the air down here would not be nearly so dense as it is, and indeed would not be fitted to supporting life. A man ascending a mountain or rising in a balloon leaves heavy layers of air below and has an ever-lightening weight above so that the atmosphere around him becomes constantly more thin, more difficult to breathe. This difficulty is felt to a severe extent by those who climb the greater mountains. Within certain limits of height, the air is only more light and exhilarating, because a little less dense than on the plane. But as its rarity increases, the breath gets short, the heart's action is quickened, the sense of oppression grows painful. If the ascent could be continued indefinitely, death from suffocation would result. The loftiest mountaintop upon the earth stands only about five and a half miles above sea level. No man has ever yet climbed to such a height, and probably no man ever will. It might not be impossible to exist for a while upon the summit, but one can hardly imagine any man able to reach any such level by climbing. The thinness of the air must long before have so reduced his powers as to render active exertion out of the question. If some means could be devised for bearing him to the summit of Mount Everest, loftiest of the Himalayan range, he would probably, when there, be fit for little more than to lie panting on the ground. Mount Everest has never yet been scaled by men, though ardent mountaineers long ago reached to a level of over 19,000 feet in the Himalayas. This too has been done with the monsters of the Andes chain, once supposed to be the highest mountains in the world, though now known to be far surpassed by the giants of North India. In the beginning of the present century, Humboldt made a vigorous attempt to scale Chimborazo, one of the loftiest of the Andes. He and his party suffered severely from sickness, giddiness, and difficulty in breathing, and the attempt proved a failure. Not tell over 70 years later was the ascent actually accomplished by Mr. Wimper. This time too, the daring climbers were almost incapacitated by weakness, headache, fever, and breathlessness. Yet, with desperate resolution, they held on till the summit was gained. After camping for a night at the level above the utmost height of Mont Blanc, they stood at length victorious, nearly 20,000 feet above the sea. The ascent of the last thousand feet, we are told, occupied five hours. For a large tract of extraordinarily soft snow had to be crossed, and it was found necessary to flog every yard of it down, and then to crawl over it on all fours. Such exertions at so great a height, and in so rare an atmosphere, speak well for the indomitable spirit of the travellers. De Soceur, ascending Mont Blanc in August 1787, suffered from extreme distress and exhaustion. On the highest ridge, he had to halt every 15 or 16 steps, sometimes even to lie down. And the robust guides with him were an absolute danger of fainting. The same excessive weakness was felt by certain other well-known climbers in 1844. But this experience is by no means universal. The effect of the rarefied air differs extremely with different individuals. Moreover, use greatly modifies and even to some extent does away with these effects. In the Andes, there are cities full of people at heights of 12,000 or 13,000 feet, and no inconceivable results from the thinner air. Carried upward passively in a balloon, without effort, men have risen higher than the greatest mountains. Mr. Coxwell and Mr. Glacier, in their celebrated aerial voyage of 1862, are believed to have mounted seven miles above the sea. No little peril and suffering were involved, alike from the extreme thinness of the air, and from the bitter cold. The wish to fly like a bird is an old wish among men. Perhaps it is a form of the new restlessness, which dislikes to be tied down anywhere. Perhaps it partakes of the excelsior feeling, which would feign reach regions inaccessible. Tied down, we undoubtedly are to the lower depths of the air ocean, and inaccessible to the higher regions, undoubtedly are to us. Various mad attempts at flying have been made from time to time, more or less disastrous to the makers of them. When, however, near the close of the 18th century, a balloon was first made and sent up, men thought that they had had last one mastery of the atmosphere. They did not at once find out that floating is not flying. That the balloon, at its best, is still only an unmanageable despot, a despot over the men whom it carries, and itself a complete prey to the despotic winds and breezes. No means of steering or guiding a balloon has yet been discovered. Authors note, attempts are now being made to construct an airship able to plow its way through the opposing winds, whether successful or no, time will show. Where the air flows, the balloon goes, fast or slowly, according to the degree of wind. No balloon ever cuts its way through the wind or travels contrary to a breeze. It is simply swept to and fro by the atmosphere, as a cork is born to and fro by the ocean. The first public balloon ascent took place in June 1783, a fire balloon made of linen and filled with smoke went up from near Lyon, and a fervor of excitement followed. Silk balloons filled with hydrogen gas were made next, and the earliest ascent of man followed. A successful, though perilous attempt across the channel took place about two years later. Many aerial journeys were made, some ending well, some fatal to the unfortunate voyagers. As the dangers of these attempts became better known, and as their comparative uselessness for almost all except scientific purposes grew more apparent, public interest in the matter faded. During the early half of the present century, balloons were little thought of, but more lately there has been a revival of interest. Some very remarkable ascent have been made by the famed aeronauts, Mr. Coxwell and Mr. Glacier. One or two of these are especially worth mentioning. In their second ascent from Wolverhampton, the balloon sprang rapidly upwards and in about ten minutes was hidden by a cloud. It reappeared, vanished again, was seen at a height of perhaps three miles, disappeared anew, then gleamed in the far distance as a transparent ball shining moon-like in the sunbeams. The journey lasted from about one o'clock till half past four, and in that interval the balloon ascended four miles and a half. The voyagers suffered from severe sea sickness, though not from bleeding of the nose or singing in the ears, popularly expected on such occasions. They had enough to bear without these additions. Mr. Glacier held manfully to his task, observing and noting down the state of the atmosphere minute by minute, despite sickness, brain pressure, violent headaches, and a pulse at one hundred and eight per minute, all due to the rarity of the air. The view seen from above must indeed have been marvelous. No veil of intervening clouds shut off what lay below, and the earth was visible, not as a rounded surface, but as a seeming hollow, with a distant horizon raising high all around, like the rim of a saucer, or an inverted watch glass. The intense black blue of the sky, as seen from great altitudes, is well known to mountain climbers. Here, however, the blue seemed to be everywhere, a mighty expanse of pure blue filled the vast hollow, reaching to unlimited depths above, an immense shoreless ocean, the ocean of air in which these daring voyagers floated. A boundless sea of ever-changing clouds, piled in mountain masses, and dazzling the eyes with their snowy glare, followed more or less the lines of the horizon, often closing in below to shut off the solid ground. As the blue rose higher, the pervading blue grew brighter, and earthly sounds waxed faint. One mile high, human voices might still be heard, raised in a shout. Two miles high, only a dog's sharp bark could be distinguished. Since a balloon moves with the moving air, there are no jars or jolts, no struggles to advance, as with a ship at sea, nothing resists its passage. The movements of a balloon seem, indeed, to be characterized by a singular quietness, so far as regards the voyagers' sensations. When it first rises, the earth appears to drop away. When it descends, the earth appears to rise. There is little consciousness of motion. This delusion was quaintly expressed by a certain American aeronaut. He was, he says, preparing to come down gently when the earth bounced up against the bottom of his car. A more terse description could scarcely be offered. The most remarkable ascent known was that of Mr. Glacier and Mr. Cockswell on the 5th of September, 1862, when they rose seven miles. If we remember that Mount Everest of the Himalayas is nearly twice the height of Mont Blanc, and that the voyagers were floating a mile and a half higher than the height of Mount Everest's topmost peak, we shall better imagine the perils of this excursion. No human beings have ever ascended further. The marvel was that they returned to earth alive. In those lofty regions of air-ocean, no living creatures exist. The voyagers pass through the boundless silent solitudes, silent, except for the hurried beating of their own hearts, the sound of their own panting breath, and the sharp ticking of their watches, and the clang of the valve door. On leaving earth, the thermometer stood at 59 degrees. Soon afterward, the balloon passed through masses of clouds, thousands of feet in depth, then came out into dazzling sunshine with a deep blue sky above and cloudless mountain masses of billowy cloud below. As they rose, they released at intervals a captive pigeon. One set free at a height of nearly five miles fell downward like a stone. Of two others taken higher, one died of the cold, and the other was stupefied. When they reached five miles above the sea, the temperature was below zero. Still upward, further upward rose the resolute pair. Then, blinding darkness and insensibility seized Mr. Glacier. Had he been alone, he would never have revived. With no one to open the valve, the balloon must have carried him onward into yet higher and deathlier regions, where for a lack of air he would have perished. Even then, Mr. Cockswell did not at once give in. But he was strictly on the watch. At the seven miles level, a tremendous height, he too felt signs of failing consciousness. In a few minutes more, all would have been over with them both, and at last he yielded. It was indeed time that he should. His hands were powerless to act, but he seized the valve rope in his teeth and pulled. The gas rushed out, the balloon steadily sank. Both lives were saved, and a mighty feat had been accomplished. Yes, a mighty feat and at a tremendous height in consideration of human powers. Seven miles high would seem to be the outside limit at which animals generally can exist, even for a short time. Birds may be, to some extent, an exception. Certain birds are believed to soar occasionally two or three miles higher still. But what are seven miles? What are even ten miles compared with the four or five hundred miles of atmosphere depth? With all our utmost efforts, we and the birds still find ourselves only able to creep and flutter on or near the floor of the ocean of air. End of Chapter 1 Chapter 2 What the world would be without air What earth would be without her surrounding ocean of air? We can scarcely imagine. The atmosphere plays so extraordinary an essential a part in all around that to picture its entire absence is not easy. We see faintly on the moon something of what an airless world must be. Yet since we only see from a distance of two hundred and forty thousand miles, that does not mean much. Imagination has to come in. And imagination is apt to play us curious tricks run running after affairs which lie outside the range of human experience. No man has ever yet been to an airless world. If he could get there, he could not live there ten minutes. He would be worse off than the aeronauts seven miles above Earth's surface. They had at least some air, though, but a scanty amount, while he would have absolutely none. Without air, man and beast cannot breathe. Without air, plants and trees cannot grow. Without air, life as we know it, the lower animal life common to man and beast, is a thing impossible. Without air, our world would be, as we suppose the moon to be, a world of lifelessness. Air is the Earth's outer robe for use and for beauty, for use in modes uncountable, for beauty not so much in itself as in the softening, the diffusing, the controlling effects of its presence. Air is a mighty ocean in which all things living must dwell. Even the living things of the sea are not exceptions to this rule, for water itself is pervaded by air. A man going into and underwater does not get beyond the touch of air, only not being provided like fishes with breathing gills. He cannot make use of what is there. He cannot separate the air from the water, and so keep himself alive by breathing it. Some animals living in the water ocean are as dependent upon the air ocean as man himself for the breath of life. Wales are a remarkable example of this. They are not fishes, though often mistakenly called so, but belong to the same family of creatures as men and land quadrupeds generally. A whale is warm-blooded, has no gills and breathes atmospheric air coming to the surface for it. A whale, kept forcibly for a long while underwater, would be drowned exactly as a man would be. If a whale is thrown upon the shore, it does not die of suffocation but of inannation. A fishes gills are no more fitted to breathe air in bulk than a man's lungs are fitted to breathe air diffused in minute particles through water. The fish out of water is suffocated by getting air too rapidly, the man underwater by exactly the reverse. A whale breathes like a man, and on land it simply stars fast from lack of the incessant food required by such a huge carcass. There is a difference, certainly, between man and whale in the matter of breathing. A man has to take in fresh supplies of air constantly, and if he is beyond reach of air for more than a few minutes, he dies. A whale comes to the surface for about ten minutes, spouting out enormous supplies of used up air and taking in enormous supplies of fresh air, after which it can remain underwater for half an hour or more, some say an hour. Then a fresh bout of noisy breathing becomes an absolute necessity. This, however, is merely a matter of internal arrangement. The whale has an immense reservoir of blood, which being thoroughly purified by the air during ten minutes of vigorous breathing, serves slowly to supply the creature's requirements while below. But the need for air and the effect of that air upon the blood are much the same in man and whale. Small creatures, as well as big ones, spending much time underwater, and yet breathing air, have to come regularly to the surface. The Great Water Beetle, for instance, while able to live on land, is a very incapable being there, and seems at home only in the water. Like other insects, it has no lungs, and breathes air into its body through tiny holes in its sides. Lungs or no lungs, air it must have, or like man and whale it must die. So after the fashion of the whale, it rises to the surface to breathe, and not having the happy internal arrangement of the whale, one would expect it to be compelled to bob up incessantly for fresh air. But here we find another provision equally wonderful. The hard, polished wings of the beetle, neatly fitting and fast shut, enclose between themselves in the body a watertight hollow into which the breathing holes open. This hollow is filled with air when the creature comes to the surface of the pond, and while the little supply is being gradually breathed, the beetle may safely remain below. Not till it is used up, does a dart to the surface for fresh supply become necessary. Another such instance is seen in the water spider, a creature again which can exist on land, but is more at ease in water. When the spider dives, it carries downward countless tiny air bubbles, caught and imprisoned among the fine hairs which cover its body. This is not all. The spider has also an extraordinary power of conveying down at will between body and folded legs, a large bubble of air for a particular purpose, to supply the little home below. The said home is a cocoon spun by the female spider in readiness for eggs. Having prepared a cocoon, the spider dives with a big air bubble and lets it loose within the cocoon where it remains, driving out an equal quantity of water. Bubble after bubble being carried to the spot, all the water in the cocoon is gradually replaced by air, and the tiny dwelling becomes habitable. So much as to the need of air for living creatures. If our world had no ocean of air, there could be on earth no men, no quadrupeds, no whales or fishes, no birds or insects, no forms of life. Like the ocean of water, the ocean of air knows no repose or stagnation. What we call stillness on the most sultry of summer days does not mean absolute stillness. Though not enough wind may stir to lift a feather, yet the air is in ceaseless motion to and fro, hither and thither. The whole atmosphere is a vast and complicated system of air currents, and each lesser portion of air has its own lesser circulation. You cannot lift your hand without causing a tiny breeze. You cannot turn a wheel without making a minute whirlwind, and every separate air movement draws other movements in its train. There is water enough on earth for all needed purposes, but we should find ourselves in direful straits if the whole water carrying from lakes and rivers for men and animals had to be performed by human agencies. Far from this, a mighty apparatus is provided, the scanty aid that man can give only shows how little he is capable of. The entire atmosphere is a tremendous pumping engine, an enormous watering machine always at work, always receiving supplies of liquid from the ocean, from seas, lakes, rivers, always showering this water down again upon the land, as needful drink for plants and animals, as needful cleansing for all things. Air, the great carrier of water in its wonderful strength and restlessness, bears vast layers of cloud to and fro, wafts away superfluous damp, drenches the dry and thirsty earth, fills ponds and lakes, feeds, nay actually makes the rivers, never flags in its ceaseless energy. If clouds hang low or fogs arise, we are glad of the moving air which sweeps them elsewhere. If the soil is caked and plants droop, we are glad of the moving air which brings rain. Thus our wants are supplied, and the wide water circulation of earth is carried on. Without circulation, without motion, stir, change, there cannot be life. Stagnation must mean death. Our earth, without her ocean of moving air, would be a world of death. Without air, earth would be in great measure a soundless world, silence would rain here, as probably it does rain on the moon. Sound, as it commonly reaches our ears, depends for its very existence upon air. Let the concussion of two bodies be ever so mighty if there were no air to bear away the vibrations of that concussion, there could be no crash of sound. True, sound waves can be conveyed through a liquid or through solid as well as through air, and we might be conscious of the ground's vibrations, but our ears would hear no noise. So an airless world would be a silent world. Without air, supposing we could ourselves exist, we should hear no trickling brooks, no rush of waterfalls, no breaking ocean waves, no sighing of the wind, no whisper of leaves, no singing of birds, no voices of men, no music, no thunder, no one of the thousand concomitant sound waves which together make up the babble and murmur of country and town. Those only who are perfectly deaf can know what such silence means. Without air, our world would not be in darkness, for light does not, like sound, depend mainly upon air for its transmission. Light travels through regions where air is not, and if light is communicated by waves, they are not waves of air. But, though the absence of air would not deprive the earth of light, it would make a very great difference in the kind and degree of light received. Without air, the blue sky would be black as ink, stars would glitter coldly in the daytime beside a glaring sun, deep shadows would alternate with blinding dazzle, and all the soft tints of sunrise and sunset would be wanting. Earth would be like the almost airless moon, all fierce whiteness and utter blackness, with no gray shades, no rosy gleams, no golden evening clouds, nay without air there could be no clouds. On the moon is no twilight, for no air particles float about, reflecting the sunlight from one to another, and forming a soft veil of brightness to reach farther than the direct sunlight alone can reach. Sunbeams travel straight to earth, unbending as arrows in their flight, and unaided they cannot creep any distance round a solid body, though they may be reflected or turned back from it. But the air breaks up the sunbeams, bends them, diffuses them, spreads them about, surrounds us with a delicate lacework of woven light. A sunbeam traveling through space is invisible till it strikes upon some object. If that object is solid, the light of the sunbeam is partly absorbed, partly reflected. If the object is transparent, the sunbeam passes through and onward. Few substances, if any, are perfectly transparent. We call air transparent, yet it is so only in a measure. Each sunbeam passing through the atmosphere loses part of its brightness, by the way, and so the great glare of the sun is softened before it reaches the lower depths of the air ocean. The sun's rays are rays of heat as well as of light. While the atmosphere softens the glare, giving us shade and twilight, it also modifies the extremes of temperature, from which, without air, we should suffer. When the sun goes down, although we are often conscious of a chill, it is not the instant and overwhelming chill which we should feel but for the atmosphere. All day long, the sun has been warming the earth and air. When his direct rays are withdrawn, the warm air for a while keeps its warmth and gives over of that warmth to us. We talk often of warm winds and cold winds from different quarters. By warm winds, we mean air that has passed over a warm surface of land or sea, so gathering up and bringing heat to us. By cold winds, we mean air that has passed over a cold surface of land or sea, so parting with some of the heat it had in a measure and reaching us in a chilled condition. People in England are very much warmer than their friends across the Atlantic living no further north. Here the weather is mild when there it is bitterly cold. There they are frozen up when here we have only a little fitful frost and snow. The main reason for this difference is that abundance of soft warm air comes drifting over us from a certain ocean current called the Gulf Stream, flowing northward in our direction from the tropics. Our friends across the ocean receive alike abundance of cold air from a cold ocean current flowing southward from the frigid zone. All this would be altered had we know in folding Ocean of Air. End of Chapter 2. Chapter 3 of The Ocean of Air Meteorology for Beginners This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. The Ocean of Air Meteorology for Beginners by Agnes Gibain. Chapter 3 The Weight and State of Air If one would understand the atmosphere as a whole, one must learn something about the laws which govern its movements. That air is a substance and therefore is heavy like any other substance has already been explained. We are apt to talk of things as heavy and not heavy as if some things had weight and some had not, but every substance without exception has weight. A certain gas called hydrogen does not commonly fall downward but rises through the air upward. If we wish to send a balloon towards the sky, we only have to fill it with hydrogen gas and it is sure to ascend. Yet hydrogen gas is a substance and has weight. Only its weight is so very much less than the weight of common air that the air particles fall naturally below and press the lighter particles of hydrogen upward. This is how a balloon rises, not because it has no weight, but because it weighs less than air. A cork has weight yet in water it springs to the top because it weighs less than the same bulk of water. A feather, light as we count it, has weight and if dropped in a closed vessel emptied of air it will reach the bottom quite as fast as a lump of iron. From its light and spreading make it is easily buoyed up and carried along by the slightest breeze, but if the air is still it soon finds its way downward. Until nearly the middle of the 17th century nobody so much as suspected the fact that air had weight. When Galileo was an old man of 76 he was the first to gain a glimpse of the long hidden truth and his pupil Torricelli followed out his experiments proving him to be in the right. Weight is caused by a wonderful force or power which holds sway not only on earth but in the sun and the planets and throughout the universe, the force of gravitation. Every substance attracts every other substance towards itself with a greater or less degree of strength dependent on the size, the make and the distance of each. If no substance attracted any other substance there would be no such thing as weight. When we speak of a mass of iron being heavy we mean that the earth draws it downward. When we speak of the whole atmosphere having weight we mean that it too is pulled earthward. The attractive force which causes all objects to draw nearer together when not prevented we know by its effects and by its effects only. We see what it does not what it is. That such a force exists we perceive. That such a law or order prevails we know. But what the force is in itself and in what mode one substance influences another none can tell us. Searches we may and rightly may into these things solving one perplexity after another we find ourselves surrounded still by baffling walls of mystery. We call attraction one of nature's laws or one of nature's forces. Either term leaves us where we stood before. The forces of nature are the forces of the god of nature. The laws of nature are the laws of the god of nature. They constitute the plan on which the universe and all that is therein are framed. And because they are his laws, his forces, and because he is our father we, his children, may well search into them with the utmost of such powers as he has given us. The air of our almost invisible ocean is often described as an elastic fluid but this gives no clear idea of its condition. A fluid may be either a liquid or a gas and liquids are by no means the same as gases. There are three distinct forms known to us of the same substance upon earth. These three states or forms are called the solid, the liquid, the gaseous. A simple illustration is to be found in the water. Suppose a man should travel to earth from some far off region of space, having never seen our common earthly substances, having never come across water in any of its various conditions. He must not, by the by, hail from the planet Mars, since there at least we have good reason to believe snow not only exists but thaws, which means the presence of water as well as of ice. Suppose on arrival he should alight first upon a green land glacier, having hard ice all around him. He would naturally describe water as a species of rock. For thus far he would know it only in the solid or frozen form. If he landed first on the border of the ocean, in a temperate climate, he would describe water as a liquid. If his first acquaintance with it were in the shape of steam escaping from a boiler he would describe it as a vapor or as a gas. He would not at once, without further observation, know that these three are one and the same substance under different forms. He would not yet know that ice can be turned into water, water into steam, steam into water, and water into ice. Nor could he guess that the force by which its presence or absence works these changes is heat. You have a solid block of ice and a certain amount of heat is brought to bear upon it. Gradually the ice becomes water. The solid is changed into a liquid, but the substance is the same. The particles which form the water are the same which form the ice, only under altered conditions. Again, more heat is brought to bear upon the water until it boils. Then gradually it changes into steam. The liquid has become vapor, but still the substance is the same. The particles which form the steam are the identical particles which form the water, and before that the ice only a change has come over them. If the steam is not allowed to escape, but is kept in a confined space and cooled down, the particles will draw together again and the steam will once more become water. If the cooling is continued, more heat being taken away until the freezing point is reached, it will turn again into ice. To the same ice which it was originally, the particles of matter are the same. The substance is not altered, it has merely passed through a series of changes of form. All solid substances are formed of minute particles, more or less closely bound together by a certain mutual attractive power, which we call the force of cohesion. Cohesion means sticking together. When we speak of the force of cohesion, we simply speak of the force of sticking together. But to speak of the parts of a substance sticking together is by no means to say why they stick together, and to talk of the cause as a force is not at all to tell how it acts. The how of this matter is again beyond us, for the attraction of cohesion is even more mysterious than the attraction of gravitation. We see both by their effects, but we do not know in what manner these effects are brought about. In a general way, when we speak of a law, we mean a command which has to be obeyed. By a law in nature, we mean rather a rule of action constantly followed by certain bodies under certain conditions. The word signifies not that the divine ruler has given definite commands which the world of matter obeys, but that the divine creator has impressed or undued each particle of matter with certain characteristics, which under the same circumstances always result in the same modes of action or work. We speak often of substances obeying certain laws, but since the word obey implies choice and a possibility of disobedience, it is hardly a correct term. Each particle of substance merely does in each set of circumstances and does inevitably that which is its nature to do. But how and why one minute particle of matter should differ so utterly in its nature from another is a profound mystery. Authors note, since writing these chapters, I have come across the following sentence in a letter of Charles Kingsley's. Everywhere, skin deep below our boasted science, we are brought up short by mystery impalpable and by the adamantium gates of transcendental forces and incomprehensible laws of which the Lord who is both God and man alone holds the key and alone can break the seal. Life of Kingsley 2.7. In addition to the force of cohesion, which holds together the particles of any substance, there is another and opposite force, sometimes described as the force of repulsion or the force of driving away. It seems singular that two such opposite forces should be at work in one lump of iron or one piece of wood, that the very particles which are trying to get closer to other particles should also be trying to get farther away from them. Many things in nature are, however, brought about by such working of opposite powers. We are well able to see a need in the present case for both if our world is to remain in its present form. Without the force of cohesion, there would be no solid substances at all. The whole earth and all it contains would be a scattered mass of loose, impalpable dust too fine for the human eye to see. There would be no shapes or forms of separate bodies were it not for the force which binds their particles together. If, on the other hand, there were no check upon cohesion, changes of an exactly opposite kind would come about. The particles of each lesser substance and of the earth itself would shrink closer and closer together till the entire mass would have grown inconceivably small and hard. This shrinking and hardening would include the ocean of air. It is what we call repulsion among the air particles which keeps them apart. If the particles of any gas are forced close together, by cold or pressure it becomes a liquid. If they are forced still closer, it changes into a solid. Probably all earthly substances are capable of taking these three forms under certain conditions, though man has not always means at his command to work the changes. There are solids, which have not yet been made liquid, and there are gases which remain persistently gases. For a long while atmospheric air resisted all efforts, but at length under intense pressure and cold it was liquefied and even rendered solid. So if no force of repulsion existed to counterbalance the force of cohesion, not only would the whole earth become amazingly small and hard, but the whole ocean of air would be transformed into a solid harder than iron. It is through the opposite workings of these two forces that we have the three forms of matter, solid, liquid, and gaseous. In a solid the cohesion is said to be greater than repulsion. In a liquid the cohesion and repulsion are said to be equal. In a gas the repulsion is said to be greater than the cohesion. The particles of a gas struggle to get far apart from one another, unless confined on all sides they fly away and are lost. This would happen with our entire atmosphere if it were not for the controlling power of gravitation. The ocean of air is tied and bound to the earth by gravitation alone. In upper layers, where both the attraction of the earth and weight of the overlying air are lessened, the separate air particles float much more widely apart, yet even there, even on the outmost limits of the atmosphere, they are still under the restraint of gravitation. At the level of sea the atmosphere presses upon each square inch of the ground, and of every creature and thing upon earth with a weight of about 15 pounds. The whole atmosphere all around the whole earth is said to weigh about 11 millions of millions of pounds. So really it is not astonishing that the lower layers of air should be packed tightly together. It seems extraordinary that we do not ourselves feel the pressure, since it is upon us as well as upon the earth. On each square inch of our bodies the atmosphere bears hard with a force of 15 pounds weight, which means over 2000 pounds upon the square foot, and something like 30,000 pounds upon the whole body of an ordinary sized man. Try to lift a load of 100 pounds, then think what it would be to have 20 times that weight lying upon your chest. You could only expect to be crushed and killed. Some such result would doubtlessly come about, but for the fact that the pressure existed everywhere. Air is not only outside, but also inside us. It not only surrounds, but pervades our frames. We, it is true, are in the air, and no less truly the air is in us. Pressure from without is counterbalanced by resistance from within. This fact of air pressure can be shown by an ordinary air pump. Before the air is pumped out of the bell-shaped glass it may be lifted by a finger, but when the air is gone from within the outside air bears upon it so heavily as to make the glass immovable under one's utmost efforts. It is literally jammed down upon the wooden stand. If the glass were not very strong and shaped for resistance it would be shivered into pieces. Atmospheric pressure, acting equally in all directions, is due to its make as a gas. The particles of gas are in a state of ceaseless unrest, forever hurrying to and fro one among the other with immense speed, perpetually striking against each other and against the sides of any vessel in which the gas may be confined. Each particle of air is always on the rush, always striking and rebounding from its neighbors, and any solid or liquid substances which lie in its path. If a tumbler is filled to the brim with water and a piece of blotting paper or other soft paper is laid over it the glass may be carefully turned upside down and the whole body of water will be borne up by the wet paper. That which keeps the paper in position is neither more nor less than the ceaseless cannonade of invisible air particles, millions of millions of minute pellets of air banging upwards each instant against the paper from outside and holding it up. It is this incessant battery of air particles which constitutes the pressure of air against the sides of a vessel, upward, downward, within, without, and always. It is this which, as above stated, when acting within a closed box or within the limits of the human frame is sufficient completely to counterbalance the outside pressure. It is in this way through the unceasing hail of innumerable air particles on the basin of a barometer that the mercury is held up in the barometer tube. The same explanation serves also for the rising of water in a pump. Moreover, the degree of pressure varies at different times and in different places. A cubic foot of common air near the surface of the earth generally weighs a little more than an ounce and a quarter. In other words, it generally presses with a degree of force not downwards only but in all directions. Generally, not always. The degree of pressure is proportional to the number of air particles within the cubic foot of air. The more dense a certain portion of air is, that is to say the more closely its particles are packed together, the heavier its pressure. Thus the weight of the atmosphere generally caused by gravitation increases the density of air near the surface of the earth and thereby increases its pressure. The amount of pressure is also increased by heat. If a cubic foot of air is enclosed in a vessel of the same size and is then heated, the pressure against the top, bottom, and sides of the inside of the vessel becomes greater. Because heat increases the energy of the air particles and so adds to the force of their battery. Chapter 4 of the Ocean of Air Meteorology for Beginners This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Recording by Elizabeth Miles. The Ocean of Air Meteorology for Beginners by Agnes Gebern. Air as a Mixture. Chapter 4. Air as a Mixture The air, breathed by us and by all living creatures upon earth, is not a simple gas, but a mixture of gases. Now there are more ways than one in which different substances can be mingled together. You may put a lump of sugar into a cup of tea and stir well. The sugar vanishes, yet it is still there. The separated particles float in the liquid sweetening it. Though not seen, they may be tasted. No chemical change has taken place, no real union of two substances into one. The tea remains tea, the sugar remains sugar. Or you may mix together a small quantity of powdered iron with powdered sulfur. Mix thus they are not united. The iron is iron still, the sulfur is sulfur still. But push the mixed powder into a little heap and touch it with a lighted match. A red glow will creep through the hole and an entirely new black powder will be the result. Formed itself out of iron and sulfur, yet in itself neither iron nor sulfur, but an utterly different thing. The iron is gone, the sulfur is gone, and something else has sprung into being. This is chemical change. It is the combining of the two or more separate substances into another and different substance. It is not the mere mixing together of two substances which remains still the same that they were before. Every substance that we see or know is either simple or compound. If simple it consists of one original substance which so far as we at present know cannot be broken up into other substances. If compound it is formed out of the union of other substances and therefore it can by one mode or another be broken up. Iron is a simple substance. A mass of pure iron cannot be divided by the chemist into any other substances. It can be melted into a liquid and transformed into a gas, but the liquid and the gas are iron still. Gold is another. It can be melted and with enough heat it might be vaporized, but the gold always remains gold undergoing no real change. The chemist can split up or analyze many things, but when he comes to a simple substance he has reached a shut door and can make no further advance. It would not be safe to assert that all so-called simple substances are absolutely simple. They may be compound though man has not yet discovered the fact, but in relation to our knowledge they are at least for the present simple. Water is a compound substance. It is made of two gases, oxygen and hydrogen. The two gases separate are each invisible. When united they are seen and known as the liquid substance water, the solid substance ice, the gaseous substance steam or vapor. Simple substances are also called elementary substances or elements. About 67 are known. A few among the 67 are enormously abundant, while others are scarcely ever met with. They fill much the same place in the world of matter as the alphabet fills in the world of literature. All words are made out of the letters of the alphabet variously put together. All substances are either simple, that is they are single letters of the alphabet or else they are made up out of simple substances variously combined. The air of the atmosphere is a simple mixture of two simple substances nitrogen gas and oxygen gas. A mixture, not a chemical combination. The two are mingled together much as tea and sugar are mingled, floating in close companionship without becoming one. No change has passed upon the nature of either and no third substance is formed. Each gas keeps its own character. Oxygen is rather heavier than nitrogen, so one would expect the oxygen sometimes to sink the nitrogen to rise, but this is not the case. Almost invariably, air is found to be a mixture of the two gases in the same proportions. No doubt this is more or less due to the ceaseless movements of air, the perpetual mixing by winds. Whether a portion of air is examined from a mountaintop, from a level plain or from a deep mine, the mixture is almost exactly the same. Variations there are enough to tell upon man's health, yet they are at most extremely slight. The amount of nitrogen in the air is always about four times as much by measure, footnote, by measure, not by weight, since oxygen is the heaviest, end of footnote, as the amount of oxygen. If one should divide a certain quantity of air into five almost equal parts separating the two gases, one part should be oxygen for nitrogen. Or, to put it differently, suppose you have four gallons of nitrogen gas and you wish to transform it into common air. You must add one gallon of oxygen gas and shake them well together. Besides the two chief gases of which air is made, a small quantity of carbonic acid gas and a still smaller quantity of ammonia gas are also to be found in it. If you had 10,000 gallons of air, one fifth of which would be oxygen and four fifths nitrogen, only about one gallon of carbonic acid gas would be distributed thinly through the whole. As for ammonia gas, only one gallon in amount is spread among one million gallons of air. So we can hardly speak of these two as having a large share in the make of the atmosphere. They are rather a slight addition to it, a kind of flavoring, if one may so express it. Yet, carbonic acid gas, despite its comparatively small amount, is of the greatest possible importance, and indeed, though the quantity may seem slight viewed beside the other gases, it is by no means slight as a whole. The entire mass of carbonic acid gas, always present in the ocean of air, is simply enormous. Beside the gases, there is invariably more or less water in the atmosphere, hidden away in the form of vapor. If you had 1,000 gallons of air, you would find spread through them from 4 to 16 gallons of invisible water gas or vapor. The amount of carbonic acid gas and of water vapor is not constant, but varies incessantly at different times and in different places. There are also countless specks of matter floating through the air ocean, especially in its lower regions. But the amount of these specks I cannot give in gallons, probably no one has ever even tried to reckon their quantity. We have now found in the air we breathe these things. Nitrogen gas, oxygen gas, carbonic acid, ammonia gas, vapor of water, floating dust. 5. Air as a part of Earth Most people know that the Earth is not at rest, but is in perpetual motion, spinning like a huge top, and also rushing like an enormous ball round the sun. I want you now to think steadily about the spinning movement of Earth, about her daily whirl, top like, round and round, upon her own axis. If you stick a knitting needle through an orange and spin the orange upon the knitting needle, keeping the needle itself fixed, this will help you to see the daily rotation of Earth. The Earth is a huge globe about 8,000 miles straight through, from the north to the south pole, and from the equator on one side to the equator on the other side. The movement of Earth's surface as she spins is very little indeed near the poles, while on the equator the surface travels round at the rate of over 1,000 miles an hour. A man standing on the equator is carried along at that rate always without the slightest effort on his own part, born onward irresistibly by the rush of the solid ground on which he stands. Let's suppose he gets into a balloon and rises into the air one, two, three miles upward, what happens then? Why then of course, as the Earth whirls away from beneath him, he will be left behind, floating in the still atmosphere. What more simple? Well, yes, it sounds very simple. A most natural answer. There was a time when it would have been counted entirely correct. Yet the consequences of such a state of things would be by no means simple. We know a little more about the matter now. Suppose the balloon to start from the island of Samatra, exactly on the equator, to the south of Psi M. The solid ground there spins perpetually round the center of the Earth at the rate of 1,000 miles an hour. The balloon rises upward in the calm air on a still day towards the blue tropical sky. As the surface of the Earth below rushes from west to east at this tremendous speed, more than 14 times as fast as the fastest express train, you would expect the man in the balloon to be left behind. I do not mean that he would be blown by winds in any particular direction, but merely that as the Earth rushes away the balloon would be stationary, floating placently at rest. If this were the case, and the balloon could remain undisturbed by currents of air, the man would only have to float reposefully in the same spot, and in the course of 24 hours the whole circle of the equator would pass beneath him. He would see in succession the Indian Ocean, Africa, the Atlantic Ocean, South America, the Pacific Ocean, and lastly the islands from which he started. A wonderful vista indeed. But practically a man in such a position has no such magnificent diorama presented to him. He rises from Sumatra, and the Earth's surface is spinning at the rate of 1,000 miles an hour, spinning along but not spinning away. Whereas he rises he looks down upon Sumatra still. If the air were perfectly breathless he might rise to any height at which he could breathe, and Sumatra still would lie outspread below. If the wind were easterly he would find himself soon looking down on the Indian Ocean. If the wind were westerly he would travel towards the Pacific Ocean. The explanation lies in the fact that the atmosphere is attached to the Earth and whirls with the Earth. Air, remember, is a material substance, not solid, but formed of particles of matter. It is held fast to Earth by the force of gravitation. Each particle of air has a chair in the motion of the solid body to which it belongs, to which it is tied by its own weight, that weight being due to gravitation. Earth and atmosphere are practically one, and they act as one in the daily whirl. I do not say that there is no lagging behind of upper layers of air anywhere upon Earth. But taking the matter generally, the entire atmosphere spins with the spinning Earth. The air in any one part has precisely the same motion as the ground on or near where it rests. So a balloon or a bird in the air is carried with the air in its daily rush around the Earth's axis. Imagine what the results would be if things were otherwise, if the air remained fixed while the surface of the Earth whirled away beneath. We all know the effects of a high wind or a hurricane. Now wind is simply air in motion. If the air were utterly at rest, you may say that at all events, we could then have no wind. But the effects of wind may be brought about in two ways. One way is by the motion of air against still objects, the other is by the motion of objects through still air. Whether the air rushes fast against a man or whether a man rushes fast through the air makes no real difference. In either case, the effect is the same. In either case, he is struck with the same degree of force by the resisting particles of air. If the atmosphere were at rest, there would perhaps not be a wind, strictly speaking. Nevertheless, if you on the equator were careening at the rate of 1000 miles an hour through still air, the effects upon yourself would be precisely the same as if you were at rest and the wind were careening past you at that rate. A powerful hurricane travels at the rate of 90 miles or more an hour and the most solid buildings often cannot stand against it. The heavy pressure of air particles crowding one upon another in their frantic rush will level massive walls, tear off roofs, lay trees flat. You may suppose then the destruction that would be wrought by a hurricane blowing not at the rate of 90 miles, but of 1000 miles an hour. The results must prove equally overwhelming whether caused by the rush of air past us or by our rush through the air or in either case the fierce resistance of air particles would be the same. A man standing on an engine going at the rate of 60 miles an hour has a powerful wind in his face. The air may be equally still, no breeze stirring it, yet he steady advance along the motionless air particles will cause him to have exactly the same sensations as if he were at rest and a strong gale were blowing. To all intents and purposes it is a gale. The pressure of air resisting his passage is in no wit different whether his movement or its movement be the cause. In the case that we have supposed of the solid earth revolving while the atmosphere above remains at rest, the resistance of the air in equatorial regions would be tremendous past imagination. Nothing loose or movable on earth's surface could stand against it. Men and animals, trees and buildings, rocks and stones, boats and ships, nay the whole mass of ocean water itself would be kept back by the enormous pressure of the atmosphere acting as a terrific hurricane and would be swept in one rushing mel torrent of ruin over the revolving surface of the earth. In the contrary direction to earth's whirl, complete chaos and destruction could alone ensue. This widespread destruction is prevented by the simple fact that as the earth whirls, her enfolding vesture of air whirls with her. Practically indeed, things not only are so but must be so. The atmosphere weighted by gravitation clinging to earth must move with the earth. That the earth should revolve and the atmosphere not revolve is an impossibility. The layer of air lying close to earth's surface is dragged round by the earth and drags round the layer above which in its turn does the same for the next and so on upward. Or rather if the atmosphere were by any possibility at rest it would in this manner be speedily set going. Once made to revolve it is certain to go on revolving until stopped by some other force. Yet so calm, so soft, so steady as the motion, despite its great speed that we upon earth carried smoothly along by the solid ground and the elastic air are not conscious of it by sensation. The same partaking of the motion of another body may be seen on a smaller scale in common life. Suppose a ship to be sailing over the sea and a man standing on the deck. That man is born onward by no exertion of his own. He remains perfectly still, he makes no effort to advance. With relation to the ship, though not with relation to the sea, he is at rest. He does move, but only as a part of the ship, as sharer in the ship's motion. A man seated in a train has a motion in common with the train. As the train travels, so he travels. And so the air in the closed compartment travels. Outside the particles of still air strike the moving train with sharp resistance. Inside both air and man are born along as part of the train. The resistance of air particles to any body passing among them may appear a slight matter. Yet it works a weighty part in the affairs of this world, not to speak of other worlds, where also unfolding atmospheres exist. If you draw your hand quickly through water, you are aware of a counter pressure. The water seems trying to hinder or push it back. A man swimming in the sea or rowing a boat is keenly conscious of this. The same resistance, though not to the same extent, is found in the ocean of air. The particles of a gas are less densely placed, less close together than those of a liquid. Therefore, a body moving in their midst can more easily thrust them aside to make way for itself. Still, there always is a measure of resistance. This fact of air resistance is a serious item for consideration in the matter of motion generally. There are many bodies on earth at rest and many in motion. Those at rest have usually to move sooner or later. Those in motion come as a rule sooner or later to rest. Two main rules govern the condition of objects in motion or at rest. One is well known, the other not so well known. They are these. One, a body at rest is never set in motion except by force. Two, a body in motion is never brought to rest except by force. The first of the two everybody will ascend to at once. We all know that a ball does not set itself rolling, that a train will not start itself, that a cannon cannot fire itself off. A certain amount of power or force must be exerted upon a body from outside to make it move, and it must always be enough force to cause the particular movement required. A man's hand can throw or roll a ball of india rubber, but a man's hand cannot start a train. Even in the case of a man walking, though in a sense he does set himself going, yet this only means that his will takes the place of the outside force and causes his muscles to act. But to say that a body in motion can only be stopped by force, that is another matter. Do we not all know that nothing on earth continues moving forever? Do we not all know that everything inevitably stops sooner or later? Have we not seen for ourselves how the swift cannonball, the whirling grindstone, the spinning top, the swinging pendulum all come to repose? Did not our ancestors search in vain for perpetual motion, wasting time and money in a hopeless quest because no motion of bodies on earth ever is perpetual? Yes, true enough all this, yet nonetheless true is the rule given. Motion is never stopped but by force. No single body will ever move unless it is made to move. Once set going it will never cease moving unless it is brought to rest by the exercise of a counter force. For motion is as naturally permanent as rest, rather difficult to believe is it not? Yet this is a fundamental fact. You see a big rock lying on a mountainside and you are quite ready to assent when somebody remarks that the rock will not stir without being made to do so. There is a certain reluctance to change its present condition, a stubbornness or inertia about the rock. This inertia chains it to the spot where it lies until some outside force shall be exerted to set it going. But suppose such a force is exerted and the great rock is sent rolling, leaping, crashing fiercely down the steep mountainside. We have now a new state of things. The rock is no longer at rest, it is in motion. The stubbornness, the reluctance to change its present state, a state of motion, the inertia in short of the rock, continue as before though manifested differently. Then the rock was at rest and it would not move without being made to move. Now the rock is in motion and it will not stop without being made to stop. Not stop! You are hardly so ready to assent to this as to the former statement. Of course it will stop, so soon as it reaches level ground. Yes, of course. Concussion with the level ground will prove to be a sufficient checking force. I did not say that the rock would never cease to move. I only said that it would not stop without the exercise of force. No doubt a sufficient force will be exercised by the resisting ground. In this world there always is a sufficient checking force to bring all moving bodies to rest. That fact does not in the least attract from the truth of the opposite fact that, if no checking force existed, the body would not cease to move. Take a tennis ball in your hand and fling it high. That tennis ball will go on forever unless stopped. Fire a bullet from a rifle. That bullet will speed onward forever unless stopped. Set a grindstone whirling fast. That grindstone will whirl forever unless stopped. Make a top spin steadily. That top will spin forever unless stopped. These things always are stopped, but they do not stop themselves. They do not come to rest of themselves. Always invariably, sufficient force is used by something or somebody to bring them to a state of repose. The great checks to continued movement on earth are commonly reckoned as two, friction and the resistance of the air. These two may almost be reduced to one, for the resistance of the air is really only a delicate form of friction. It means simply the striking and rubbing of the tiny particles of air against anything passing through the midst of them. The attraction of the earth is another great hindrance to motion, but this also comes under the head of friction. The earth draws the moving or falling body downward, then friction against the ground, rocks or water causes it to stop. So by friction we mean the touching and rubbing of other substances. If you touch a spinning top ever so lightly with your finger, you will see at once how great is the checking power of a touch to anything in motion. As a rule the word is used with reference to solid bodies, but the resistance of water particles and air particles practically amounts to the same thing. A great cannon ball is dispatched from the mouth of a huge cannon, whizzing, whirling, tearing along, ready to destroy, ought that may lie in its path. The force which has started the ball is the gun powder explosion, the sudden change of a solid into a gaseous form, and the consequent tremendous pressure of gaseous particles fighting to escape, thus overcoming utterly the stubborn inertia of the ball at rest. But when once the ball is off, some other force equal in degree is needed to overcome the stubborn inertia of the ball in motion before it can be brought to rest once more. Only instead of being a single sharp exercise of power penned up in a tiny space in one moment, it may be a slow and continued exercise of force, gradually acting. If no such force is exerted, the ball will rush on forever, always in a straight line, always at the same speed. First, the air particles begin. It is wonderful to think that such weak floating infinitesimal specks of matter can have the smallest effect upon a mighty cannon ball. Perhaps you have never been underneath a cannon ball fired from a large gun, and so have not heard the furious rush and whiz of its passage among those air particles, sounding like a small express train, careering over your head. If you had, you would realize that the opposition which they offer is by no means contemptible. Singly they are soft and weak, but banded together, acting in concert, they are strong. From the moment that the ball leaves the cannon, they are at work. Each air particle, which lies in the path of the ball, only to be fiercely thrust aside, only to seem an utter failure, has done its tiny task. The air particles alone, unaided, would in time bring the great ball to rest. But something else is at work also, in conjunction with the struggling particles of air. Earth is dragging at the ball with her ceaseless pull. The force of the explosion may send it far upward, yet soon the pull of earth tells, and a downward curve begins which presently lands the ball upon the ground. For a while still it may leap and bound forward, but with every crash of contact a further check is given, and at length the moving body is at rest. Yet, remember, the cannon ball would never of itself have traveled in a curved path or with slackening speed. It would have gone on interminably, always straightforward, always at the same speed. Without the resistance of the air, the attraction of the earth, and the friction of the ground, it would not have stopped. So there was a sufficient cause for the starting of the cannon ball. There was a sufficient cause for its moving in a bent path. There was a sufficient cause for its going more slowly. There was a sufficient cause for its coming to a standstill. There is always a sufficient cause for every movement, and for every change of movement in a moving body, just as much as for any movement at all in a body hitherto at rest. We thus see distinctly that it was the inertia of the heavy cannon ball, which made a strong explosive force needful to start it in swift career. Once started, it was the very same inertia, differently shown, which made the continued resistance of air and earth needful to bring it to repose. A curious calculation has been made illustrating how great is the resistance of air particles to a body moving with great rapidity. A cannon ball is fired off and travels, let us say, some six thousand feet before touching the ground. If the air offered no resistance, it would have sped to a distance of over twenty thousand feet in one unbroken rush. The nearest approach to unceasing motion on earth is to be found in a pendulum, hung in a vacuum from a hard, fine point. There, no soft elastic atmosphere checks the steady swing. Nothing checks it, except a very slight degree of friction at the point from which it hangs. Still, some amount of rubbing always does and must exist at that point. The pendulum may swing for hours, even through a whole day, but sooner or later it has to stop. The only apparently perpetual motion of which we can speak with confidence is that of the heavenly bodies, the whirling and revolving suns and worlds. Our earth is one of those worlds. Her movements have lasted through ages unchanged, since the hand of God sent her forth upon her celestial pathway. How she was first set going, we do not know, and how long she will continue to move, we do not know. All we know is that sufficient force must have been exerted to set her whirling and revolving, and that no sufficient force has ever since been exerted to bring her to a stand still. In the wide regions of space, no air exists to check her movements. The earth carries the atmosphere with her as she rolls onward, a soft surrounding vesture, a deep, translucent ocean, a very part of herself. There is no vast ocean of air throughout space. The stars and planets roll unhindered through centuries of centuries with calm, continuous whirl. Something, indeed, there probably is, though not air, something unspeakably thinner and lighter than our atmosphere, something so rare and fine that we can scarcely more than guess at its existence. But if this something, which we call ether, does indeed extend through space and can exercise any checking force upon the heavenly bodies, it is a force so slight, so slow in action, that no results are yet apparent. To man watching with demise from the lower levels of the air ocean, the motions of the suns and worlds through thousands of years show no change. Recording by John Brandon. The Ocean of Air. Meteorology for Beginners. By Agnes G. Byrne. Chapter 7. The Uses of Oxygen. We must now learn a little more about the separate gases, which, mixed together, make our ocean of air. Wherever atmospheric air is found, it consists, as explained earlier, of about four fifths by measure of nitrogen to one of oxygen. Though the quantity of nitrogen is so much greater than that of oxygen, yet the oxygen may well claim our chief attention. Oxygen is the great life-supporting power on earth. Without oxygen, plants could not grow. Without oxygen, animals could not exist. Also without oxygen, fire could not burn. Nitrogen does little positive work in comparison, but rather fills the humble office of a make-wait and a drag upon the intense activity of its companion. One of the compounds of nitrogen from which indeed comes its name is nitr, another is nitrous oxide, well known under its old name of laughing gas. If breathed under particular conditions, it causes a kind of intoxication, and when in that state men act in a strange and laughable manner. It is now much used by dentists and also by surgeons in smaller surgical cases for the deadening of pain. As its name tells, it is formed of nitrogen and oxygen. Nitrogen is found in the solid earth, as well as in the ocean of air. It has a share in the make of plants and animals. No unimportant share in the case of animals, for without nitrogen, neither blood nor muscle could be formed. Pure nitrogen is colorless, tasteless, and scentless. It is called inert, or slow and heavy, from its seeming reluctance to unite with other substances. It does unite with some, but not readily. Oxygen on the other hand seems always to hold itself open to combine as fast as possible with almost any other substance. One might liken these two gasses, with their opposite characteristics, to two opposite characters often seen in man. The first, dull, slow, holding aloof from other people, cautious, and cold, rarely making friends. The second, eager, sparkling, warm-hearted, prepared to rush into enthusiastic friendship with nearly anybody who may come in his way. Nor is it difficult to understand how if these two lived and worked together, the slowness, caution, and coldness of the one would act as a check upon the eagerness of his impulsive companion, just as nitrogen does upon oxygen. Suppose you have two closed jars, one full of pure nitrogen gas, the other full of pure oxygen gas, and also a little wax candle, like those which are used for Christmas trees. If you light the candle and lower it into the nitrogen gas, not letting the gas escape, and not letting any air get in, the flame will at once go out. But if you put the lighted candle into the jar of oxygen gas, it will burn much more quickly and brightly than in common air. Nitrogen gas cannot support combustion. In common air, oxygen does all that work, and nitrogen only hinders it. Pure oxygen, apart from nitrogen, is a tremendous quickener of fire. Suppose, instead of putting a lighted candle into either of the closed jars, you were to put a poor little mouse into each. I'm not advising this act, for if needless it would be cruel. But suppose it had to be done. The mouse in the nitrogen would quickly die of suffocation. It would not be poisoned, for strictly speaking, nitrogen is not poisonous. The little creature would simply die from lack of oxygen, would die because the nitrogen is dull and powerless to do for his little frame what is needed to keep it going. Nitrogen can no more support life than it can support fire. The mouse placed in pure oxygen would not be suffocated, but it too would die, though not so quickly, of the too strong oxygen. We all know the effects of a very strong pure air. That is, air which has rather more than the usual quantity of oxygen. It excites and exhilarates the whole frame. To breathe perfectly pure oxygen for any length of time would have the same effect, but in a very intense degree. It would be an extreme case of what is called overstimulation. If our atmosphere could get rid of all its nitrogen and consist of oxygen alone, the whole of mankind would be speedily laid low or driven mad with desperate fevers burning away their strength. And if any building in a town caught fire the whole town would be ruined, the flames spreading with such ruthless fury that all efforts to check them would be in vain. Thus we find the need of the dull, deadening nitrogen to control the too exciting oxygen. The oxygen has in fact to be weakened for our use, just as many a strong medicine has to be diluted with water before we can safely drink it. Nitrogen gas has been changed by chemists to a liquid and even to a solid described as a snow-like crystalline mass. Oxygen gas also has been liquefied and is capable of becoming a solid. In other words of being frozen. Both these are always gases on earth in their natural state. Great cold or great pressure being needed to change their state when either is combined. However, with other substances the result is often a liquid or a solid. Like nitrogen gas, oxygen is colorless, invisible, tasteless, and scentless. There are enormous quantities of oxygen on earth apart from what is constantly flowing free in the ocean of air. The rocks of earth piled often to mountainous heights are in their make nearly one half oxygen by weight. The stones big and little which lie scattered by millions on earth's surface are in their make nearly one half oxygen by weight. The soils of earth from which sprout grasses, plants, and trees are in their make nearly one half oxygen by weight. The waters of earth, seas, and rivers, ice fields, clouds, and vapor are in their make not only one half but eight ninths oxygen by weight. And when we come to examine the bodies of living things both plants and animals we find them also to contain in their make a goodly amount of oxygen. In fact if the whole of our solid globe were broken up into all its component parts that is into the separate substances of which it is composed each different substance being placed alone the heaviest supply of all would be the oxygen supply. Nearly one half by weight of the entire mass would be pure oxygen. I say distinctly by weight and not in size oxygen might be far the heaviest heap without being the biggest. Many light substances take up more room than heavy ones. If you have a gallon of water that water has in its make eight times as much oxygen as hydrogen by weight yet if the water is divided into the two gases it will be found that the hydrogen takes twice as much room or is twice as big as the oxygen for hydrogen is light and oxygen is heavy. So we see that oxygen is one of the most important elements on earth and also that we have a very large supply of it but if questioned what oxygen really is I can only answer that it is or appears to be a simple substance it will unite with or separate from other substances yet in itself it remains unchanged it can never be broken up into other substances. Seeking to analyze the make of oxygen we come to one of those fast shut doors spoken of earlier thus far seems to be uttered and we can go no farther by and by it is true science may find a mode of opening that closed door and getting through if so the mystery will only be pushed a little farther back another closed door sure to lie not far behind this is always the case with our present powers we never do or can get to the end of anything with no mystery lying beyond one might almost say that if we could that would be the greatest mystery of all that present oxygen is as to its real nature a shut door we know of its existence we see what it does and what it cannot do we are acquainted with its peculiar characteristics it's the special modes of action we are aware what we expect from oxygen in particular circumstances that is about all oxygen is by no means stationary fixed in certain positions through countless ages portions of oxygen may remain very long fixed in such solid bodies as rocks and stones though even they are subject to waste what oxygen in general is remarkable for its activity its love of change a perpetual intercourse is kept up between the oxygen of the earth of the sea and of the air between the oxygen of living creatures and of things without life oxygen is forever passing into structures and out of them again becoming part of organisms and leaving them uniting with other elements and breaking loose from them entering into the make of liquids only to separate itself anew feeding flame and life and growth but in the very act finding renewed freedom ready always to be caught and fixed by the next substance which may come in its way under the right conditions yet seldom content to stay long in any combination or escape is possible thus a ceaseless circulation of oxygen is kept up there are other circulation systems to be noticed later there is the circulation of blood in a living animal there is the circulation of air there is the circulation of water but this circulation of oxygen is not the least remarkable of them all almost all substances will unite with oxygen to form fresh substances these others springing from the union are called oxides and the act of combining is called oxidation to cause such union a certain amount of heat must be brought to bear upon the different substances and not always the same amount some substances require more some less before they will unite whenever chemical combinations take place under the influence of heat there is also a giving off of heat by the bodies as they unite this is the invariable rule though the heat may not always be felt or seen by us if the union takes place very slowly as in the forming of iron rust the heat given out will be gentle and imperceptible if the union takes place fast as in the burning of a piece of wood there will be sensible warmth and a red glow perhaps flame if the union takes place with extreme suddenness as in a gunpowder explosion there will be great heat a bright flash of flame and a loud noise end of chapter seven recording by john brandon