 CHAPTER 40 THE ACTION OF FROST IN WATER PIPES AND ON BUILDING MATERIALS Popular science has penetrated too deeply now to render necessary any refutation of the old popular fallacy which attributed the bursting of water pipes to the thaw following a frost. Everybody now understands that the thaw merely renders the work of the previous freezing so disastrously evident. Nevertheless, the general subject of the action of freezing water upon our dwellings is not so fully understood by all concerned as it should be. Builders and house owners should understand it thoroughly as most of the domestic miseries resulting from severe winters may be greatly mitigated, if not entirely prevented, by scientific adaptation in the course of building construction. Nowadays, tenants know something about this and select accordingly. Thus, the market value of a building may be increased by such adaptation. Solids, liquids, and gases expand as they are heated. This great general law is, however, subject to a few exceptions, the most remarkable of which is that presented by water. Let us suppose a simple experiment. Imagine a thermometer tube with its bulb and stem so filled with water that when the water is heated nearly to its boiling point, it will rise to nearly the top of the long stem. Now let us cool it. As the cooling proceeds, the water will descend and this descending will continue until it attains the temperature marked on our ordinary thermometer as 39 degrees or more strictly 39 and two-tenths, then a strange inversion occurs. As the temperature falls below this, the water rises gradually in the stem until the freezing point is reached. This expansion amounts to one 7,690 second part of the whole bulk of the water, or 100,000 parts become 100,013. So far the amount of expansion is very small, but this is only a foretaste of what is coming. Lower the temperature still further, the water begins to freeze, and at the moment of freezing, it expands suddenly to an extent equaling one-fifteenth of its bulk, i.e. of the bulk of so much water as becomes solidified. The temperature remains at 32 degrees until the whole of the water is frozen. Fortunately for us, the freezing of water is always a slow process, for if this conversion of every 15 gallons into 16 took place suddenly, all our pipes would rip open with something like explosive violence. But such sudden freezing of any considerable quantity of water is practically impossible on account of the latent heat of liquid water, which amounts to 142 and a half degrees. All this is given out in the act of freezing. It is this giving out of so much heat that keeps the temperature of freezing water always at 32 degrees, even though the air round may be much colder. No part of the water can fall below 32 degrees without becoming solid, and that portion which solidifies gives out enough heat to raise 142 and a half times its own quantity from 31 degrees to 32 degrees. The slowness of thawing is due to the same general fact. An instructive experiment may be made by simply filling a saucepan with snow or broken ice and placing it over a common fire. The slowness of the thawing will surprise most people who have not previously tried the experiment. It takes about as long to melt this snow as it would to raise an equal weight of water from 32 degrees to 174 degrees. Or if a pound of water at 174 degrees be mixed with a pound of snow at 32 degrees, the result will be two pounds of water at 32 degrees. 142 degrees will have disappeared without making the snow any warmer. It will all have been used up in doing the work of melting. The force with which the great expansion due to freezing takes place is practically irresistible. Strong pieces of ordinance have been filled with water and plugged at muzzle and touch hole. They have burst in spite of their great thickness and tenacity. Such being the case, it is at first sight a matter of surprise that frozen water pipes, whether of lead or iron, even stand at all. They would not stand but for another property of ice, which is but very little understood, namely its viscosity. This requires some explanation. Though ice is what we call a solid, it is not truly solid. Like other apparent solids, it is not perfect rigid but still retains some degree of the possibility of flowing, which is the characteristic of liquids. This has been shown by filling a bombshell with water, leaving the fuse hole open and freezing it. A shell of ice is first formed on the outside, which of course plugs up the fuse hole. Then the interior gradually freezes but the expansion due to this forces the ice out of the fuse hole as a cylindrical stick, just as putty might be squeezed out, only that the force required to mold and eject the ice is much greater. I have constructed an apparatus which illustrates this very strikingly. It is an iron syringe with cylindrical interior of about half an inch in diameter and a terminal orifice of less than one twentieth of an inch in diameter. Its piston of metal is driven down by a screw. Into this syringe I place small fragments of ice or a cylinder of ice fitted to the syringe and then screw down the piston. Presently a thin wire of ice is squirted forth like vermicelli when the dough from which it is made is similarly treated, showing that the ice is plastic like the dough, provided it is squeezed with sufficient force. This viscosity of ice is displayed on a grand scale in glaciers, the ice of which actually flows like a river down the glacier valley, contracting as the valley narrows and spreading out as it widens, just as a river would. But moving only a few inches daily according to the steepness of the slope and the season, slower in winter than in summer. Upon this and the slowness of the act of freezing, depends the possibility of water in freezing in iron pipes without bursting them. Even iron yields a little before bursting but ordinary qualities not sufficiently to bear the expansion of one fifteenth of their contents. What happens then? The cylinder of ice contained in the tube elongates as it freezes, provided always the pipe is open at one or both ends. But there is a limit to this, seeing that the friction of such a tight fitting core, even of slippery ice, is considerable and if the pipe be too long, the resistance of this friction may exceed the resistance of tenacity of the pipe. I am unable to give any figures for such length. The subject does not appear to have been investigated as it should be, and as it might well be by our wealthy water companies. We all know that lead pipes frequently succumb, but a little observation shows that they do so only after a struggle. The tenacity of lead is much less than that of iron, about one twentieth that of ordinary wrought iron, but it yields considerably before breaking. It has, in fact, the property of viscosity similar to that of ice. At Woolwich the lead used for elongated rifle bullets is squirted like the ice in my syringe above described, powerful hydraulic pressure being used. This yielding saves many pipes. It would save all new pipes if the lead were pure and uniform, but as this is not the case they may burst at a weak place, the yielding being shown by the bulge that commonly appears at the broken part. From the above it will be easily understood that a pipe which is perfectly cylindrical, other conditions equal, will be less likely to burst than one which is of varying diameter, as the sliding from a larger to a smaller portion of the pipe must be attended with great resistance, or a certain degree of block beyond what would be due to the mere friction along a pipe of uniform diameter. Let us now consider the relative merits of lead and iron as material for water pipes in places where exposure to frost is inevitable. Lead yields more than iron and so far has an advantage this however is but limited. As lead is practically inelastic every stretch remains and every stretch diminishes the capacity for further stretching. The lead thus stretched at one frost is less able to stretch again and has thus lost some of its original tenacity, hence the superiority of new lead in pipes. Iron is elastic within certain limits and thus the iron pipe may yield a little without permanent strain or distress and if its power of elastic resistance is not exceeded it regains its original size without becoming sensibly weaker. Add to this its great tenacity its non-liability to the indented or otherwise to vary in diameter and we have a far superior material. But this conclusion demands some qualification. There is iron and iron cast iron and wrought iron and very variable qualities of each of these. I need scarcely add that common brittle cast iron is quite out of the question for such purposes though there is a new kind of cast iron or semi-steel coming forward that may possibly supersede all other kinds. But this opens too wide a subject for discussion in the present paper the main object of which has been a popular exposition of the general physical laws which must be obeyed by the builder or engineer who desires to construct domestic or other buildings that will satisfy the wants of intelligent people. The mischievous action of freezing water is not confined to the pipes that are constructed to receive or convey it. Wherever water may be if that water freezes it must expand in the degree and with the force already described. If it penetrates stone or brick or mortar or stucco and freezes therein one of two things must occur either the superfluous ice must exude at the surface or to neighboring cavities or the saturated material must give way and split or crumble according to the manner and degree of penetration. To understand this the reader must remember what I stated about the little understood viscosity of ice as well as its expansion at the moment of freezing. Bricks are punished but not so severely as might be anticipated seeing how porous are some of the common qualities especially those used in London. They are so amply porous that the water not only finds its way into them but the pores are big enough and many enough for the ice to demonstrate its viscosity by squeezing out and displaying its crystalline structure in the form of snow-like efflorescence on the surface. This may have been observed by some of my readers during a severe frost. It is commonly confounded with the whorefrost that whitens the roof of houses but which is very rarely deposited on perpendicular wall faces. The mortar most liable to suffer is that which is porous and pulverulent within but has been cleverly faced or pointed with a crust or more compact material. This outer film prevents the exuding of the expanding ice crystals is thrust forth bodily and retained by ice cement during the frost but it falls in scales when this temporary binding material thaws. Mortar that is compact throughout does not suffer to any appreciable extent. This is proved by the condition of the remains of Roman brickwork that still exist in Britain and other parts of Europe. Some of the old shingle walls at Brighton and other parts of the South Coast where the chalk for lime burning was at the builder's feet and where his mortar is so thickly laid between the irregular masses of flint also show the possible duration of good mortar. The Jerry builder's mortar made of the riddlings of burnt clay ballast and dust hole refuse just flavored with lime crumbles immediately because these materials do not combine with the lime as fine, salacious sand gradually does to form an impermeable glassy silicate. Stucco is punished by two distinct modes of action. The first is where the surface is porous and the water permeates accordingly and freezes. This of course produces superficial crumbling which should not occur at all upon good material protected by suitable paint. The other case, very deplorable in many instances, is where the water finds a space between the inner surface of the stucco and the outer surface of the material upon which it is laid. This water when frozen of course expands and wedges away the stucco bodily causing it to come down in masses at the thaw. This however only occurs after severe frost as the ordinary mild frost of our favorite climate seldom endure long enough to penetrate to any notable depth of so bad a conductor as stone or stucco. It is worthy of note that water is a still worse conductor than stone. Building stones are so various both in chemical composition and mechanical structure that the action of freezing water is necessarily as varied as the nature of the material. The highly salacious granites or rather porphyries that commonly bear the name of granite are practically impermeable to water so long as they are free from any chemical decomposition of their feldspathic constituents. But when we come to sandstones and limestones or intermediate material, very wide differences prevail. The possible width of this difference is shown in the behavior of the unselected material in its natural home. Certain cliffs and mountains have stood for countless ages almost unchanged by the action of frost. Others are breaking up with astonishing rapidity in spite of apparent solidity of structure. The Matterhorn or Mont-Servin, one of the most gigantic of the giant Alps, 15,200 feet high, is rendered especially dangerous to ambitious climbers by the continual crashing down of fragments that are loosened when the summer sun melts the ice that first separated and then for a while held them in their original places. All the glaciers of the Alps are more or less streaked with moraines, which are fragments of the mountains that freezing water has detached. Our stone buildings would suffer proportionally if some selection of material were not made. Generally speaking, this selection is based upon the experience of previous practical trials. Certain quarries are known to have supplied good material of a certain character, and this quarry has therefore a reputation which is usually of no small value to its fortunate owner. Other quarries are opened in the neighborhood wherever the rock resembles that of the tested quarry. Sometimes, however, materials are open for selection that have not been so well tested and a method of testing which is more expeditious and less expensive than constructing a building and watching the result is very desirable. The subject of testing building materials in special reference to their resistance of frost was brought before the Academy of Science of Paris by M. Brard some years since. In his preliminary experiments he used small cubes of the stone to be tested, soaked them in water, and then exposed them to the air in frosty weather or subjected them to the action of freezing mixtures. Afterwards he found that by availing himself of the expansive force which certain saline solutions exert at the moment of crystallization he could conveniently imitate the action of freezing without the aid of natural or artificial frost. Epsom salts, niter, alum, sulfate of iron, globbers salts, etc. were tried. The last named globbers salt or sulfate of soda which is very cheap was found to be the best for the purpose. His method of applying the test is as follows. Cut the specimens into two inch cubes with flat sides and sharp edges and corners. Mark each specimen with a number either by ink or scratching and enter in a book all particulars concerning it. Make a saturated solution of the sulfate of soda in rain or distilled water by adding the salt until no more will dissolve. Perfect saturation being shown by finding after repeated stirring that a little of the salt remains at the bottom an hour or two after the solution was made. Heat this solution in a suitable vessel and when it boils put in the marked specimens one by one and keep them immersed in the boiling solution for half an hour. Take out the specimens separately and suspend them by threads each over a separate vessel containing some of the liquid in which they were boiled but which has been carefully strained to free it from any solid particles. In the course of a day or two as the cubes dry they will become covered with an efflorescence of snow like crystals. Wash these away by simply plunging the specimen into the vessel below and repeat this two or three times daily for four or five days or longer. The most suitable vessel for the purpose is a glass beaker sold by vendors of chemical apparatus. In comparing competing samples be careful to treat all alike i.e. boil them together in the same solution and dip them an equal number of times at equal intervals. Having done this the result is now to be examined. If the stone is completely resistant the cube will remain smooth on its surfaces and sharp at its edges and corners and there will be no particles at the bottom of the vessel. Otherwise the inability of the stone to resist the test will be shown by the disfigurement of the cube or the small particles wedged off and lying at the bottom of the liquid. Care must be taken not to confound these with crystals of the salt which may also be deposited. These crystals are easily removed by adding a little more water or warming the solution. For strict comparison the fragments thus separated should be weighed in a delicate balance such as is used in chemical analysis. End of chapter 40 recording by Melanie Young. Chapter 41 The Corrosion of Building Stones About 50 years ago two eminent French chemists visited London and rather astonished the natives by a curious feature of their dress. They wore on their hats large patches of colored paper coming as they did from Paris. Many suppose that this was one of the latest Paris fashions and the dandies of the period narrowly escaped the compulsion to follow it. They probably would have done so had the Frenchman shown any attempt at decorative shaping of the paper. They neglected this because it was litmus paper and their object in attaching it to their hats was to test the impurities of the London atmosphere. Blue litmus paper as everybody knows nowadays turns red when exposed to an acid. The French chemists found that their hat decoration has changed color and indicated the presence of acid in the air of London. But when they left the metropolis and wandered in the open fields their blue litmus paper retained its original color. By using alkaline paper they contrived to collect enough of the acid to test its composition. They found it to be the acid which is formed by the burning of sulfur and attributed existence to the sulfur of our coal. At this time the domestic use of coal was scarcely known in Paris. Subsequent experiments have proved that they were right. That the air of London contains a very practical quantity of sulfurous and sulfuric acids which are due to the combustion of that yellow shiny material more or less visible in most kinds of coal and has been occasionally supposed to be gold. It is iron pyrites a compound of iron and sulfur. When heated the sulfur is separated and burns producing sulfurous acid which exposed to moist air gradually takes up more oxygen and becomes sulfuric acid which in concentrated solution is oil of vitriol. In the air it is very much diluted by diffusion but it is still strong enough to do mischief to some kinds of building materials. In manufacturing towns such as Birmingham and Sheffield the quantity of this acid in the air is much greater than in London and there its mischief is consequently more distinctly visible. The Church of Saint Philip which stands nearly in the middle of Birmingham and is surrounded by an old church yard was so corroded by this acid that the stone peeled away on all sides and its condition was most deplorable. The tombstones were similarly disintegrated on their surfaces and inscriptions quite obliterated. It became so bad that a few years ago restoration was necessary and it was newly faced accordingly. Some of the old tombstones that are preserved may still be seen against the church wall and their peculiar structure is well worthy of study. They display a lamination or peeling away due to unequal corrosion, certain layers of the material of the stone having evidently been eaten away more rapidly than others. Anybody visiting Birmingham may easily examine these as Saint Philip's Church yard is situated between the two railroad stations of New Street and Snow Hill and is but two minutes walk from either. Other stone buildings in the town have suffered but in very different degrees and some have quite escaped proving the necessity of careful selection of material wherever cold fires abound. In Birmingham the action of cold fires is assisted by other sources of acid vapor. The process of pickling brass castings that is brightening their surface by dipping first in common nitric acid pickle ackee and then in water is attended with considerable evolution of acid fumes. Besides this very widespread use of acid there are several chemical manufacturers that throw still more acid into the air immediately surrounding them. As an example of the action of the atmospheric acids of London upon building stones I have but to name the houses of parliament which have only been rescued from superficial ruin by the patchwork replacing of certain blocks of stone and various devices of salacious and other washings that have been carried out at great cost to the nation that such an unsuitable material should have been used is disgraceful to all concerned. The ruin commenced before the building was finished. At the time when its erection commenced there were abundant evidences of the ruinous action of London atmosphere on some kinds of stone and the capability of others to resist it. For a while many modern buildings are peeling and crumbling some of the oldest in the midst of the city show scarcely any signs of corrosion. The Birmingham and Midland Institute was established and in practical operation a few years before the present noble building was erected. I was the first teacher there and conducted the science classes in the temporary premises in Cannon Street. Having observed with some interest the disintegration of St. Philip's Church and other buildings I was anxious for the safety of the new institute buildings and accordingly made some experiments upon the material proposed to be used by the architect. My method of testing was very simple and as the practical result has verified my anticipations I think it might be adopted by others. First I immersed some lumps of the stone in moderately strong solutions of sulfuric and hydrochloric acid successfully and observed whether any visible action occurred after some days. There was none. Then I roughly tested the crushing pressure of small samples in their natural state and subjected similar sized pieces to the same test after they had been immersed in the acids. I found thus that there were no evidence of internal disintegration even after several days immersion and therefore inferred that the stone would stand the acid vapors of the Birmingham atmosphere. This has been the case with that portion of the building that was built of the material I tested. As I know nothing of the stone which is used for the extension of the building under the present architect Mr. Chamberlain, I am unable to make any forecast of its probable durability. The experiments I made at the time named with this and other building materials justified the conclusion that the worst of all material for exposure to acid atmospheres is sandstone, the particles of which are held together by limestone or are otherwise surrounded by or intermickled with limestone and that the best of ordinary material is a pure sandstone quite free from lime. I do not here consider such luxurious material as granite or porphyries. Compact limestone such as good homogeneous marble stands fairly well although it is slowly corroded. The corrosion however in this case is purely superficial and tolerably uniform. It is a very slow washing away of the surface without any disintegration such as occurs where a small quantity of limestone acts as a binding material to hold together a large quantity of salacious or sandy material and where the agglomeration is porous and the stone is so laid that a downward infiltration of water can take place for it must be remembered that although the acid originally exists as vapor in the air it is taken up by the falling rain and the mischief is directly done to the stone by the acidified water. This of course is very weak acid indeed that which I used for testing the stone was many thousand times stronger but then I exposed the stone for only a few days instead of many thousand days. As above stated my experiments were but rude but I think it would be quite worthwhile to construct crushing apparatus capable of registering accurately the pressure used and to operate with standard solutions of acid upon carefully squared blocks of standard size and thus to make comparative tests of various samples of stone when competitions for building materials are offered. In the case of Birmingham and Midland Institute building there was no such competition the choice was left entirely to the architect and my examination was unofficially conducted upon the material already chosen with the intent of protesting if it failed as it stood the test I merely reported the results informally to the architect the late Sir Edward Berry no further action being demanded. End of chapter 41 recording by Tom Mack chapter 42 of science in short chapters this is a lepervox recording all lepervox recordings are in the public domain for more information or to volunteer please visit lepervox.org recording by Rachel Marie science in short chapters by W. Mateo Williams chapter 42 fire clay and anthracite for household fireplaces whether open or closed these may be regarded as the material and the fuel of the future and should be more generally and better understood than they are the merits of fire clay were fully appreciated and described nearly a hundred years ago by that very remarkable man Benjamin Thompson count of Rumford any sound scientific exposition of the relative value of fire clay and iron as fireplace materials can be little more or less than a repetition of what he struggled to teach at the beginning of the present century it is impossible to fairly understand the subject unless we start the firm grasp of first principles the business before us is to get as much heat as possible from fuel burning in a certain fashion and to do this with the smallest possible emission of smoke substances that are hotter than their surroundings communicate their excessive temperature in three different ways first by conduction second by convection third by radiation all of these are operating in every form of fireplace but in very different proportions according to certain variations of construction to demonstrate the conduction of heat hold one end of a pin between the finger and thumb and the other end in the flame of the candle the experiment will terminate very speedily then take a piece of a lucifer match of the same length as the pin and hold that in the candle this may become red hot and flaming without burning the fingers as the pin did at a much lower temperature it matters not whether the pin beheld upwards downwards or sideways heat will travel throughout its substance and this sort of traveling is called conduction and the pin a conductor of heat the conducting power of different substances varies greatly as the above experiment shows metals generally are the best conductors but they differ among themselves silver is the best of all copper the next calling for comparison sake the conductivity of silver one thousand that of copper is 736 gold 532 brass 236 iron 119 marble and other building stones 6 to 12 porcelain five ordinary bricker only four and fire bricker less than this thus we may at once start upon our subject with the practical fact that iron conducts heat 30 times more readily than does fire break convection is different from conduction in as much as it is affected by the movements of the something which has been heated by contact with something else water is a very bad conductor of heat much worse than fire brick and yet as we all know heat is freely transmitted by it as when we boil water in a kettle if however we place the water in a fire clay kettle and applied the heat to the top we should have to wait for our tea until tomorrow or the next day when the heat is applied below the hot metal of the kettle heats the bottom film of water by direct contact this film expands and thus being lighter rises through the rest of the water heating other portions by contact as it meets them and so on throughout the heat is thus conveyed and the term convection is based on the view that each particle is a carrier of heat as it proceeds air conveys heat in the same manner so may all gases and liquids but no such convection is possible in solids the common notion that heat ascends is based on the well-known facts of convection it is the heated gas or liquid that really ascends no such preference is given to an upward direction when heat is conducted or radiated radiation is a flinging off of heat in all directions by the heated body radiation from solids is mainly superficial and it depends on the nature of the heated surface the rougher and the more porous the surface of a given substance the better it radiates bright metals are the worst radiators lamp black the best and fire brick nearly equal to it to show the effect of surface take three tin canisters of equal size one bright outside the second scratched and roughened the third painted over with a thin coat of lamp black he'll eat with hot water at the same temperature and leave them equally exposed their rates of radiation will then be measurable by their rates of cooling the black will cool the most rapidly the rough canister next and the bright one the slowest radiant heat may be reflected like light from bright surfaces the reflecting substance itself becoming heated in the proportion which diminishes just as its reflecting powers increase good reflectors are bad radiators and bad absorbers of heat and the power of absorbing heat or becoming superficially hot when exposed to radiant heat is exactly proportionate to radiating efficiency fire clay is a good absorber of radiant heat that is it becomes readily heated when near to hot coals or flames without acquiring actual contact with them it is an equally good radiator let us now apply these facts to fire clay in fireplaces beginning with ordinary open grates used for the warming of apartments first supposing that we have an ordinary old fashioned great all made of iron front sides and back as well as bars and next that we have another of similar form and position but all the fire box and the back and cheeks of the great made of fire clay it is evident that the fire clay not an actual contact with the coals but near to them will absorb more heat than the iron and must become hotter even at the same temperature it will radiate much more heat than iron but being so much hotter this advantage will be proportionately increased an open fireplace lined throughout with fire clay thus throws into the room a considerable amount of its own radiation in addition to that thrown out from the coal but what becomes of this portion of heat when the fireplace is all of metal it is carried up the chimney by convection for the metal well that parts with less heat by radiation gives up more to the air by direct contact therefore if we must burn our coals inside the chimney we lose less by burning them in a fire clay box than in a metal box Count Wumford demonstrates this and described the best form of open fire grate that can be placed in an ordinary English hole in the wall fireplace the first thing to be done according to his instructions is to break up your large square fireplace recess so that the back of it shall come forward to about four inches from the front inside face of the chimney thus contracting the throat of the chimney just behind the mantle to this small depth Wumford's device for sweeping need not be here described the sides or covings of this shallowed recess are now to be sloped inwards so that each one shall horizontally be at an angle of 135 degrees to the plane of this new back and meet it at a distance of six or more inches apart according to the size of great required the covings will thus spread out at right angles with each other and leave an annular opening to be lined with fire brick and run straight up to the chimney the fire bars and great bottom to be simply let into this as far forward as possible by this simple arrangement we get a fire grate with a narrow flat back and out sloping sides all these three walls are a fire brick the back radiates perpendicularly across the room and the sloping sides radiate outwards instead of merely across the fire from one to the other as when they are square to the walls at Wumford's time our ordinary fireplaces with square recesses now we have adopted something like a suggestion in the sloping sides of our registered rates and we bring our fireplaces forward we have gone backwards in material by using iron but this after all may be merely do the iron mongry interest overpowering that of the bricklayers the preponderance of this interest in the south Kensington exhibition may account for the fact that Wumford's simple device was not to be seen in action there it could not pay anybody to exhibit such a thing as nobody can patent it and nobody can sell it I have seen the Wumford arrangement carried out in office fireplaces with remarkable success to apply it anywhere requires only an intelligent bricklayer a few bricks and some iron bars although nobody exhibited this a very near approach to it was described in an admirable lecture delivered at south Kensington by mr. Fletcher of Warrington in one respect mr. Fletcher goes further than count Wumford in his application of fire clay he makes the bottom of the firebox a slab of fire clay instead of ordinary iron fire bars this demands a little more trouble and care in lighting the fire owing to the absence of the bottom draft but when the fire is well started the advantages of this further encasing and fire clay are considerable they depend upon another effect of superior radiant and absorbent properties of fire clay that I will now explain so far I have only described the beneficial effect of its radiation on the room to be heated but it performs a further duty inside the fireplace itself being a bad conductor it does not readily carry away the heat of the burning coal that rests upon it and being also an excellent absorber it soon becomes very hot that is superficially hot or hot where its heat is effective this action may be seen in a common register stove with fire clay back and iron sides when the fire is brisk the back is visibly red hot well the sides are still dull if after such a fire has burnt itself out we carefully examine the ashes they will be found more fine dust in contact with the fire brick than with the iron that is evidence of more complete combustion there and one of the advantages justly claimed by mr. Fletcher is that with his solid fire clay bottom there will be no unburned cinders nothing left for the incombustible mineral ash of the coal economy and abatement of smoke are the necessary con commitments of such complete combustion a valuable wrinkle was communicated by mr. Fletcher the powdered fire clay that is ordinarily sold is not easily applied on account of its tendency to crumble and peel off the back and sides and stove after the first heating in order to overcome this and obtain a fine compact lining mr. Fletcher recommends the mixing of the fire clay powder for the solution of water glass silicate of soda instead of simple water it acts by forming a small quantity of glassy silicate of alumina which binds the whole of the clay together by its fusion when heated landowners and in fact englishmen generally have either to regarded anthracite as a museum mineral and a curiosity rather than an everyday coal scuttle commodity if it is to be the fuel of the future it is very desirable that we should all know something about its merits and demerits as well as the possibility of supply anthracite is a natural coke from its position in the earth and its relations to betuminous coal as well as from its composition we had justified in regarding it as a coal that was originally betuminous but which has been altered by heat acting under great pressure in the great coal field of south wales to which we must look for a main supply of anthracite we are able to trace the action of heat in producing a whole series of different classes of coal in a single scene which at one part is highly betuminous soft flaming coal like the walls end then it becomes harder and less betuminous then semi-betuminous steam coal then less and less flaming until at last we have the hard shiny form of purely carbonaceous coal that may be handled without soiling the fingers and which burns without flame like coke or charcoal this change proceeds as the seam extends from the east towards the west in some places the coal at the base of the hill may be anthracite well that on the outcrop above it may be betuminous an artificial anthracite may be made by heating coal in a closed vessel of sufficient strength to resist the expansion of the gases that are formed it differs from coke in being compact is not porous and therefore of course much denser a given weight occupying less space that we englishmen should be about the last of all the coal using peoples to apply anthracite to domestic purposes is a very curious fact that so it is in america it is the ordinary fuel and this is the case in all other countries where it is obtainable at the price of betuminous coal our perversity in this reflect shows that the more striking when we go a little further into the subject by comparing the two classes of coal in reference to our methods of using them and when we consider the fact that our south wales anthracite is far superior to the american our open fires only do their small fraction of useful work by radiation their convection is all up the chimney such being the case and we being theoretically regarded as irrational beings it might be supposed that for our national and especially radiating fireplaces we should have selected a coal of a special radiating efficiency but instead of this we do the opposite the flaming coal is just that which flings the most heat up the chimney and the least into the room and as though we were all struggling to destroy as speedily as possible the supposed physical basis of our prosperity we select that coal which in our particular fireplaces burns the most wastefully if we had closed iron stoves with long stove pipes in the room giving to the air the heat they had obtained by the convective action of the flame and smoke there might be some reason for using the flaming coal as the flame would thereby do useful work but as it is we stubbornly persist in using only the radiated heat and at the same time select just the coal which supplies the smallest quantity of what we require no scientific dissertation is necessary to prove the superior radiating power of an anthracite fire to anybody who has ever stood in front of one this is most strikingly demonstrated by those greats that stand well forward and are kept automatically filled with the radiant carbon let us now see why anthracite is a better radiator than bituminous coal this is due to its chemical composition of all the substances that we have upon the earth carbon in its ordinary black form is the best radiator anthracite contains from 90 to 94 percent of pure carbon bituminous coal from 70 to 85 and much of this being combined with hydrogen burns away as flame on a rough average we may say that the fixed or solid carbon capable of burning with smokeless flameless glow amounts to 65 percent in ordinary british bituminous coal against an average of 92 percent in british anthracite the advantages of anthracite as a fuel for opening radiating grates are nearly in the proportion of these figures besides this it contains about half the quantity of ash thus we see that from a purely selfish point of view and quite irrespective of our duty to our fellow citizens as regards polluting the atmosphere anthracite is preferable to ordinary coal on economical grounds supposing we can obtain it at the same price as bituminous coal which is now the case another great advantage of anthracite is its cleanliness it may be picked up in the fingers without soiling them and it is similarly cleanly throughout the house it produces no blacks no grimy dust and if it were generally in use throughout london one half of the house cleaning would be saved white curtains blinds etc might hang quite four times as long and then come down not half so dirty as now the saving in soap alone without counting labour where it once returned a handsome percentage on the capital outlay required for reconstructing all our fireplaces let us now look on the other side and ask what are the disadvantages of anthracite and why is it not at once adopted by everybody there is really only one disadvantage vis-à-vis the greater difficulty in starting an anthracite fire practically this is considerable seeing that laziness is universal and ever ready to find excuses when an innovation is proposed that stands in its way to light an anthracite fire in an ordinary fireplace the bellows are required unless a specially suitable draft or fire lighter is used some recommend that an admixture of the terminus coal should be used to start it but this is a feeble device calculated to lead to total failure seeing that the solely originator and sustainer of our ordinary use of the terminus coal is domestic ignorance and indolence and if both kinds of coal are kept in a house a common English servant will stubbornly use the easy lighting kind and solemnly assert that the other cannot be used at all the only way to deal with this obstacle the human impediment is to say this you must use or go this is strictly just as a simple enforcement of duty at the same time some help should be supplied in the way of artificial modes of creating a draft in starting an anthracite fire this may be done by temporarily closing the front of the fire by a blower or better still by selecting one of the great specially devised for burning anthracite of which so many now are made another and rather important matter is to obtain the anthracite in suitable condition it is a very hard call too hard to be broken by the means usually attend in ordinary houses for domestic purposes it should always be delivered broken up of suitable size from that of an egg to a coconut for furnaces of course large lumps are preferable then again anthracite must not be stirred and poked about once fairly started it burns steadily and brightly demanding only a steady feeding the best of the special greats are more or less automatic in the matter of feeding and thus the trouble of lighting is fully compensated by the absence of any further trouble as regards the supply this for London and the greater part of England will doubtless be derived from the great coal field of south wales the total quantity of available coal in this region after deducting the waste and getting was estimated by the government commissioners at thirty two thousand four hundred fifty six millions of tonnes it is very difficult or impossible to correctly estimate the portion of anthracite in this but supposing it to be one-tenth of true anthracite it gives us three thousand two hundred forty five millions of tonnes or about enough for the domestic supply of the whole country during one hundred years assuming that it should be used less wastefully than we are now using butuminous coal which would certainly be the case but including the imperfect anthracite the quantity must be far larger than this and we have to add the other sources of anthracite we need not therefore have any present fear of insufficient supply probably before the hundred years are ended we shall find other sources of anthracite or even have become sufficiently civilized to abolish altogether our present dirty devices and to adopt a rational methods of warming and ventilating our houses when we do this any sort of coal may be used end of chapter forty two recording by rachel marie chapter forty three of science in short chapters this is a libra vox recording all libra vox recordings are in the public domain for more information or to volunteer please visit libra vox dot org recording by melanie young science in short chapters by w matthew williams chapter forty three count rumford's cooking stoves in the preceding chapter i described count rumford's modification of the english open fire great which eighty years ago was offered to the british nation without any patent or other restrictions its non-adoption i believe to be mainly due to this it was nobody's monopoly nobody's business to advertise it and therefore nobody took any further notice of it especially as it cannot be made and sold as a separate portable article an ironmonger or stove maker who should go to the expense of exhibiting rumford's simple structure of fire bricks and a few bars described in the last chapter would be superseding himself by teaching his customers how they may advantageously do without him the same remarks apply to his stoves for cooking purposes they are not iron boxes like our modern kitcheners but our brick structures matters of masonry and all but certain adjuncts such as bars fire doors covers oven boxes etc which are very simple and inexpensive even some of rumford's kitchen utensils such as the steamers were cheaply covered with wood because it is a bad conductor and therefore waste less heat than an iron saucepan lid rumford was no mere theorist although he contributed largely to pure science his greatest scientific discoveries were made in the course of his persevering efforts to solve practical problems i must not be tempted from my immediate subject by citing any examples of these but may tell a fragment of the story of his work so far as it bears upon the subject of cooking ranges he began life as a poor school master in new hampshire when it was a british colony he next became a soldier then a diplomatist then in strange adventurous fashion he traveled on the continent of europe entered the bavarian service and began his searching reform of the bavarian army by improving the feeding and the clothing of the men he became a practical working cook in order that they should be supplied with good nutritious and cheap food but this was not all he found munich in a most deplorable condition as regards mendicity and took in hand the gigantic task of feeding clothing and employing the overwhelming horde of paupers doing this so effectually that he made his house of industry a true workhouse it paid all its own expenses and at the end of six years left a net profit of 100,000 florans i mentioned these facts in confirmation of what i had said above concerning his practical character economical cookery was at the root of his success in this maintenance of a workhouse without any poor rates after doing all this he came to england visited many of our public institutions reconstructed their fireplaces and then cooked dinners in presence of distinguished witnesses in order to show how little need to be expended on fuel when it is properly used at the foundling institution in london he roasted 112 pounds of beef with 22 pounds of coal or at a cost of less than three pence the following copy of certificates signed by the counselor of war etc shows what he did at munich we whose names are underwritten certify that we have been present frequently when experiments have been made to determine the expense of fuel and cooking for the poor in the public kitchen of the military workhouse at munich and that when the ordinary dinner has been prepared for 1,000 persons the expense for fuel has not amounted to quite 12 crootzers 12 crootzers is about four and a half penny of our money thus only 150th of a farthing was expended on cooking each person's dinner although the peas which formed the substantial part of the soup required five hours boiling the whole average daily fuel expenses of the kitchen of the establishment amounted to 120th of a farthing for each person using wood which is much dearer than coal at this rate one ton of wood should do the cooking for 10 persons during two years and six days or one ton of coal would supply the kitchen of such a family three and a half years the following is an abstract of the general principles which he expounds for the guidance of all concerned in the construction of cooking stoves one all cooking fires should be enclosed two air only to be admitted from below and under complete control all air beyond what is required for the supply of oxygen is a thief three all fireplaces to be surrounded by non-conductors brickwork not iron four the residual heat from the fireplace to be utilized by long journeys and returning flues and by doing the hottest work first five different fires should be used for different work the first of these requirements encounters one of our dogged insular prejudices the slaves to these firmly believe that meat can only be roasted by hanging it up to dry in front of an open fire their savage ancestors having held their meat on a skewer or spit over or before an open fire modern science must not dare to demonstrate the wasteful folly of the holy sacrifice their grandmothers having sent joints to a bakehouse where other people did the same and having found that by thus cooking beef mutton pork geese et cetera some fresh and some stale in the same oven the flavors became somewhat mixed and all influenced by sage and onions these people persist in believing that meat cannot be roasted in any kind of closed chamber brumford proved the contrary and everybody who has fairly tried the experiment knows that a properly ventilated and properly heated roasting oven produces an incomparably better result than the old desiccating process brumford's roaster was a very remarkable contrivance that seems to have been forgotten it probably demands more intelligence in using it than is obtainable in a present-day kitchen when the school boards have supplied a better generation of domestic servants we may be able to restore its use it is a cylindrical oven with a double door to prevent loss of heat in this the meat rests on a grating over a specially constructed gravy and water dish under the oven are two blowpipes i.e stout tubes standing just above the fire so as to be made red hot and opening into the oven at the back and above the fireplace in front where there is a plug to be closed or open as required over the front part of the top of the oven is another pipe for carrying away the vapor it is thus used the meat is first cooked in an atmosphere of steam formed by the boiling of water placed in the bottom of the double dish over which the meat rests when by this means the meat has been raised throughout its whole thickness to the temperature at which its albumin coagulates the plugs are removed from the blowpipes and then the special action of roasting commences by the action of a current of superheated air which enters below and at the back of the oven travels along and finds exit above and in front of the steam pipe before named the result is a practical attainment of theoretical perfection instead of the joint being dried and corticated outside made tough leathery and flavorless to about an inch of depth then fairly cooked an inch further and finally left raw disgusting and bloody in the middle as it is in the orthodox roasting by british cooks the hole is uniformly cooked throughout without the soddening action of mere boiling or steaming as the excess of moisture is removed by the final current of hot dry air thrown in by the blowpipes which at the same time give the whole surface a uniform browning that can be regulated at will without burning any portion or wasting the external fat rumford second rule that air be admitted only from below and be limited to the requirements is so simple that no comment upon it is needed although we have done so little in the improvement of domestic fireplaces great progress has been made in engine furnaces blast furnaces and all other fireplaces for engineering and manufacturing purposes every furnace engineer now fully appreciates rumford's assertion that excess of cold air is a thief the third rule is one which as i have already stated stands seriously in the way of any commercial pushing of rumford's kitchen ranges those which he figures and describes are all of them masonic structures not iron laundry the builder must direct them they cannot be bought ready made but now that public attention is roused i believe that any builder who will study rumford's plans and drawings which are very practically made may do good service to himself and his customers by fitting up a few houses with true rumford kitcheners and offering to reconstruct existing kitchen ranges especially in large houses the fourth rule is one that is sorely violated in the majority of kitcheners and without any good reason the heat from the fire of any kitchener whether it be a brick or iron should first do the work demanding the highest temperature roasting and baking then proceed to the boiler or boilers and after this be used for supplying the bedrooms and bathroom and the housemate etc with hot water for general use as rumford did in his house at brompton row where his chimney terminated in metal pipes that passed through a water tank at the top of the house linen closets may also be warmed by this residual heat the fifth rule is also violated to an extent that renders the words uttered by rumford nearly a century ago as applicable now as then he said nothing is so ill judged as most of those attempts that are frequently made by ignorant projectors to force the same fire to perform different services at the same time note the last words same time in the uses above mentioned the heat does different work successively which is quite different from the common practice of having flus to turn the flame of one fire in opposite directions to split its heat and make one fireplace appear to do the work of two every householder knows that the kitchen fire whether it be an old-fashioned open fireplace or a modern kitchener of any improved construction is a very costly affair he knows that its wasteful work produces the chief item of his coal bill but somehow or other he is helpless under its inflection if he has given any special attention to the subject he has probably tried three or four different kinds without finding any notable relief why is this i venture to make a reply that will cover 90% or probably 99% of these cases that he has never considered the main source of waste which rumford so clearly defines as above and which was eliminated in all the kitchens that he erected let us suppose the case of a household of 10 persons but which in the ordinary course of English hospitality sometimes entertains twice that number what do we find in the kitchen arrangements simply that there is one fireplace suited for the maximum requirements ie sufficient for 20 even though that number may not be entertained more than half a dozen times in the course of a year to cook a few rashers of bacon boil a few eggs and boil a kettle of water for breakfast a fire sufficient to cook for a dinner party of 20 is at work this is kept on all day long because it is just possible that the master of the house may require a glass of grog at bedtime there may be dampers and other devices for regulating this fire but such regulation even if applied does very little so long as the capacity of the great remains and as a matter of ordinary fact the dampers and other regulating devices are neglected altogether the kitchen fire is blazing and roaring to waste from six or seven a.m. to about midnight in order to do about three hours and a half work i.e. the dinner for 10 and a nominal trifle for the other meals in rumford's kitchens such as those he built for the barren daylurgeon filled and for the house of industry at munich the kitchener is a solid block of masonry of workbench height at top and with a deep bay in the middle wherein the cook stands surrounded by his boilers steamers roasters ovens etc all within easy reach each one supplied by its own separate fire of very small dimensions and carefully closed with non-conducting doors each fire is lighted when required charged with only the quantity of fuel necessary for the work to be done and then extinguished or allowed to die out it is true that rumpford used wood which is more easily managed in this way than coal if we worked as he did we might use wood likewise and in spite of its very much higher price do our cooking at half its present cost this would affect not merely smoke abatement but smoke extinction so far as cooking is concerned but the lighting of fires is no longer a troublesome and costly process as in the days of half penny bundles of firewood to say nothing of the improved fire lighters we have gas everywhere and nothing is easier than to fix or place a suitable bunsen or solid flame burner under each of the fireplaces an iron gas pipe perforated below to avoid clogging will do and in two or three minutes the coals are in full blaze then the gas maybe turned off the writer has used such an arrangement in his study for some years past and starts his fire in full blaze in three minutes quite independent of all female interference i have no doubt that ultimately gas will altogether supersede coal for cooking but this and all other scientific improvements in domestic comfort and economy must be impossible without the present generation of uneducated domestics whose brains with few exceptions have become torpored and wouldn't from lack of systematic exercise during their period of growth and of chapter 43 recording by melanie young chapter 44 of science in short chapters this is a liver vox recording all liver vox recordings are in the public domain for more information or to volunteer please visit liver vox.org recording by melanie young science in short chapters by w matthew Williams chapter 44 the consumption of smoke a great deal has been spoken and written on this subject but practically nothing has been done at one time i shared the general belief in its possibility and accordingly examine a multitude of devices for smoke consuming and tried several of the most promising chiefly in furnaces for metallurgical work for steam boilers and stills none of them proved satisfactory and i was driven to the conclusion that smoke consumption is a delusion and further that economical consumption of smoke is practically impossible when smoke is once formed the cost of burning it far exceeds the value of the heat that is produced by the combustion of its very flimsy flocculi of carbon it is a fiend that once raised cannot be exorcised a frankenstein that haunts its maker and will not be appeased to describe in detail the many ingenious devices that have been proposed and expensively patented and advertised for this object would carry me far beyond the intended limits of this paper i must not even attempt this for a selected few as even among them there is none that can be pronounced satisfactory the common idea is that if the smoke be carried back to the fire that produced it and made to pass through it again a recombustion or consumption of the smoke will take place this is a mistake as a little reflection will show first let us ask why did this particular fire produce such smoke everybody nowadays can answer this question as we all know that smoke is a result of imperfect combustion and knowing this it can easily be understood that to return the carbonic acid and excess of carbon to the already suffocated fire can only add smother to smotheration and make the smoky fire more smoky still there is however one case in which a fire appears to thus consume its own smoke but the appearance is delusive i refer to fires lighted from above these if properly managed are practically smokeless and it is commonly supposed that smoke passes from the raw coal below through the burning coal above and is thereby consumed the fact is however that no such smoke is formed that which under these conditions comes from the coal beneath when gradually heated by the fire above is combustible gas and this gas is burned as it passes through the fire in this case the formation or non-formation of smoke depends mainly on how this gas is burned whether completely or incompletely if the air supplied for its combustion is insufficient smoke will be formed as it is when we turn up an argant gas flame so high that the gas is too great in proportion to the quantity of air that can enter the glass chimney herein lies the fundamental principle we may prevent smoke though we cannot cure it and this prevention depends upon how we supply air to the gas which the coal gives off when heated and upon the condition of this gas when we bring it in contact with the air by which its combustion is to be affected we must always remember that coal when its temperature is sufficiently heated whether in a gas retort or fireplace gives off a series of combustible hydrocarbon gases and vapors and all we have to do in order to obtain smokeless fires is to secure the complete combustion of these now we know that to burn a given quantity of gas we must supply it with a sufficient quantity of oxygen i.e. of the active principle of the air but this is not all we all know well enough that if cold coal gas and cold air be brought together in any proportion whatever no combustion occurs a certain amount of heat is necessary to start the chemical combustion of oxygen with hydrogen and carbon which combination is the combustion or burning therefore when the coal gas and the air are brought together one or the other or both must be heated up to a certain point in order that the combustion be complete if cold there is no combustion if insufficiently heated there is imperfect combustion however well these supplies may be regulated a very simple experiment that anybody may make illustrates this when an ordinary open fire is burning brightly and clearly without flame throw a few small pieces of raw coal into the midst of the glowing coals they will flame fiercely but without smoking then throw a heap of coal or one large lump on a similar fire now you will have dense volumes of smoke and little or no flame simply because the cooling action of the large bulk of coal in the course of distillation brings the temperature of its gases below that required for their complete combustion this simple experiment supplies a most important practical lesson as well as a philosophical example the best of all smoke abatement machines is an intelligent and conscientious stoker and every contrivance for smoke abatement must in order to be efficient either be fed by such a stoker or provided with some automatic arrangement by which the apparatus itself does the work of such a stoker by supplying the fresh fuel just when and where it is wanted cornish experience is very instructive in this respect the engines that pump the water from the mines do a definitely measurable amount of work and are made to register this the stoker is a skilled workman and prizes are given to those who obtain the largest amount of duty from given engines per ton of coal consumed instead of pitching his coal in anyhow cramming his firehole and then sitting down to sleep or smoke in company with his chimney the cornish or other good fireman feeds little and often and deftly sprinkles the contents of his shovel just where the fire is the brightest and the hottest and the bars are the least thickly covered the result is remarkable a colliery proprietor of south staffordshire was visiting cornwall and went with a friend to see his works on approaching the engine house and seeing a whitewashed shaft with no smoke issuing from its mouth he expressed his disappointment at finding that the engine was not at work to all who have been accustomed to the black country where coal is so shamefully wasted because it is cheap the tall clean whitewashed shafts of cornwall also smokeless present quite an astonishing appearance this is not a result of smoke consuming apparatus but mainly of careful firing it was in the first place promoted by the high price of coal due to the cost of carriage before the cornish railways were constructed and it brought about a curious result horsepower for horsepower the cost of fuel for working cornish pumping engines has been brought below that of pumping engines and the places where the price of coal per ton was less than one half another coal famine that should raise the price of coal in london to 60 shillings per ton and keep it there for two or three years would affect more smoke abatement than we can hope to result from the present and many future south kensington efforts i need scarcely dwell upon the necessity for a due supply of air this is well understood by everybody an oversupply of air does mischief by carrying away wastefully a proportionate quantity of heat the waste due to this is sometimes very serious after reviewing all that has been done the conclusion that london cannot become a clean smokeless and beautiful city so long as we are dependent upon open fire grates of anything like ordinary construction and fed with bituminous coal is inevitable the general use of anthracite would affect the desired change but there is no hope of its becoming general without legislative compulsion and englishmen will not submit to this one of the most hopeful schemes is that which was propounded a short time since by mr scott moncreef instead of receiving our coal in its crude state he proposes that we should have its smoke producing constituents removed before it is delivered to us that it should be made into a sort of artificial semi anthracite at the gasworks by a process of half distillation which would take away not all the flaming gas as at present but that portion which is by far the richest to the gas maker and the most unmanageable in common fires we should thus have a material which instead of being so difficult to light as coke and anthracite would light more easily than crude coal and at the same time our gas would have far greater illuminating power as it would all be drawn off during the early period of distillation when it is at its richest from a given quality of coal the difference would be as 24 candles to 16 the ammonia which we now throw into the air the naptha and coal tar products which we waste are so valuable that they would pay all the expenses at the gasworks and leave a handsome profit we should thus get gas so much better that two burners would do the work now obtained from three we should get all we require for lighting purposes and plenty more for heating the intermediate profits of the coal merchant would be abolished and our solid fuel of far better quality could be supplied 20 or 30 cheaper than at present provided always that the gas monopoly were abolished a consummation most devoutly to be wished for mr. Moncreve who brought forward his scheme without any company mongering or claims for patent rights estimates the saving to london at 2,125,000 pounds per annum over and above the far greater saving that would result from the abolition of smoke in connection with this scheme i may mention a fact that has not been hitherto noted that we have perforce and unconsciously done a little in this direction already formerly london was supplied almost exclusively with wall sand and other seaborne coals of a highly bituminous consumption soft coals that fused in the grate and caked together partly owing to the exhaustion of the seams and partly to the competition of railway transit we now obtain a large proportion of hard coal from the midlands this is less smoky and less sooty and hence the metropolitan smoke nuisance has not increased quite as greatly as the population but i will now conclude by repeating that whatever scheme be chosen smoke abatement is to be achieved not by smoke consumption but by smoke prevention end of chapter 44 recording by melanie young chapter 45 of science in short chapters this is a libravox recording all libravox recordings are in the public domain for more information or to volunteer please visit libravox.org recording by jeffrey smith new orleans louisiana science in short chapters by w machu williams the air of stove heated rooms whatever opinions may be formed of the merits of the exhibits at south kensington one result is unquestionable the exhibition itself has done much indirecting public attention to the very important subject of economizing fuel and the demunition of smoke we sorely need some lessons our national progress in this direction has been simply contemptible so far as domestic fireplaces are concerned to prove this we need only turn back to the essays of benjamin thompson count of rumford published in london just 80 years ago and find therein nearly all that the smoke abatement exhibition ought to teach us both in theory and practice lessons which all our progress since 1802 plus the best exhibits at south kensington we have yet to learn this small progress in domestic heating is the more remarkable when contrasted with the great strides we have made in the construction and working of engineering and metallurgical furnaces the most important of which is displayed in the seamen's regenerative furnace a climax to this contrast is afforded by a speech made by doctor seamen's himself in which he defends our domestic barbarisms with all the conservative inconvincibility of a born and bred englishman in spite of his german nationality the speech to which i refer is reported in the journal of the society of arts december 9 1881 and contains some curious fallacies probably due to its extemporaneous character but as they have been quoted and adopted not only in political and literary journals but also by a magazine of such high scientific standing as nature see editorial article january 5 1882 page 2 19 they are likely to mislead many having already in my history of modern invention etc and in other places expressed my great respect for doctor seamen's and his benefactions to british industry the spirit in which the following plain spoken criticism is made will not i hope be misunderstood either by the readers of knowledge or by doctor seamen's himself i may further add that i am animated by a deadly hatred of our barbarous practice of wasting precious coal by burning it in iron fire baskets half buried in holes within brick walls and under shafts that carry 80 or 90 of its heat to the clouds that pollute the atmosphere of our towns and make all their architecture hideous that render scientific and efficient ventilation of our houses impossible that promote rheumatism neuralgia chillblanes pulmonary diseases bronchitis and all the other ills that flesh is heir to when roasted on one side and cold blasted on the other that i am so rabid on this subject that if doctor seamen's sir f bramwell and all others who defend this english abomination were giant when mills in full rotation i would emulate the valor of my chivalric predecessor whatever might be the personal consequences doctor seamen stated that the open fireplace communicates absolutely no heat to the air of the room because air being a perfectly transparent medium the rays of heat pass clean through it here is an initial mistake it is true that air which has been artificially deprived of all its aqueous vapor is thus completely permeable by heat rays but such as far from being the case with the water it contains this absorbs a notable amount even of bright solar rays and a far greater proportion of the heat rays from a comparatively obscure source such as the red hot coals and flame of a common fire tindal has proved that eight to ten percent of all the heat radiating from such a source as a common fire is absorbed in passing through only five feet of air in its ordinary condition the variation depending upon its degree of saturation with aqueous vapor starting with the erroneous assumption that the rays of heat pass clean through the air of the room doctor seamen's went on to say that the open fireplace gives heat only by heating the walls ceiling and furniture and here is the great advantage of the open fire and further that if the air in the room were hotter than the walls condensation would take place on them and mildew and fermentation of various kinds would be engendered whereas if the air were cooler than the walls the ladder must be absolutely dry upon these assumptions doctor seamen's condemns steam pipes and stoves hot air pipes and all other methods of directly heating the air of apartments and thereby making it warmer than where the walls the ceiling and furniture when the process of warming commenced it is quite true that stoves stove pipes hot air pipes steam pipes etc do this they raise the temperature of the air directly by convection that is by warming the film of air in contact with their surfaces which film thus heated and expanded rises towards the ceiling and on its way warms the air around it and then is followed by other similarly heated ascending films when we make a hole in the wall and burn our coals within such cavity this convection proceeds up the chimney in company with the smoke but as doctor seamen's write in saying that the air of a room raised by convection above its original temperature and above that of the walls deposits any of its moisture on these walls i have no hesitation in saying very positively that he is clearly and demonstrably wrong that no such condensation can possibly take place under the circumstances suppose for illustration's sake that we start with a room of which the air and walls are at the freezing point 32 degrees Fahrenheit before artificial heating any other temperature will do and to give doctor seamen's every advantage we will further suppose that the air is fully saturated with aqueous vapor that is just in the condition at which some of its water might be condensed such condensation however can only take place by cooling the air below 32 degrees and unless the walls or ceiling or furniture are capable of doing this they cannot receive any moisture due to such condensation or in other words they must fall below 32 degrees in order to obtain it by cooling the film in contact with them of course doctor seamen's will not assert that the stoves are steam pipes in closing the steam of course or the hot air or hot water pipes will lower the absolute temperature of the walls by heating the air in the room but if the air is heated more rapidly than are the walls etc the relative temperature of these will be lower will condensation of moisture then follow as doctor seamen's affirms let us suppose that the air of the room is raised from 30 degrees to 50 degrees by convection purely reference to tables based on the researches of renew shows that at 32 degrees the quantity of vapor required to saturate the air is sufficient to support a column of 0.182 inch of mercury while at 50 degrees it amounts to 0.361 or nearly double thus the air instead of being in a condition of giving away its moisture to the walls has become thirsty or in a condition to take moisture away from them if they are at all damn this is the case whether the walls remain at 32 degrees or are raised to any higher temperature short of that of the air thus the action of closed stoves and of hot surfaces or pipes of any kind is exactly the opposite of that attributed to them by doctor seamen's they dry the air they dry the walls they dry the ceiling they dry the furniture and everything else in the house in our climate especially in the infamous jerry built houses of suburban london this is a great advantage doctor seamen states his american experience and denounces such heating by convection because the closed stoves there made him uncomfortable this was due to the fact that the winter atmosphere of the united states is very dry even when at zero but air when raised from zero degrees to 60 degrees acquires about 12 times its original capacity for water the air thus simply heated is desiccated and it desiccates everything in contact with it especially the human body the lank and shriveled aspect of the typical yankee is i believe due to this he is a desiccated englishman and we should all grow like him if our climate were as dry as his footnote in each of my three visits to america i lost about 30 pounds in weight which i recovered within a few months of my return to the home country of english-speaking nations richard a proctor end of footnote the great fires that devastate the cities of the united states appear to me to be due to this general desiccation of all building materials rendering them readily inflammable and the flames difficult of extinction when an undesiccated englishman or a german endowed with a wholesome john bull rotundity is exposed to this super dried air he is subjected to an amount of bodily evaporation that must be perceptible and unpleasant the disagreeable sensation experienced by dr. seamans in the stove heated railway cars etc were probably due to this an english house enveloped in a foggy atmosphere and encased in damp surroundings especially requires stove heating and the most inveterate worshipers of our national domestic fetish the open great invariably prefer a stove or hot pipe heated room when they are unconscious of the source of heat and their prejudice hoodwinked i have observed this continually and have often been amused at the inconsistency thus displayed for example one evening i had a warm contest with a lady who repeated the usual praises of a cheerful blaze etc etc on calling afterwards on a bitter snowy morning i found her and her daughters sitting at work in the billiard room and asked them why because it is so warm and comfortable this room was heated by an eight inch steam pipe running around and under the table to prevent the undue cooling of the india rubber cushions and thus the room was warmed from the middle and equally and moderately throughout the large reception room with blazing fire was scorching on one side and freezing on the other at that time in the morning the permeability of ill-constructed iron stoves to poisonous carbonic oxide which riddles through red hot iron is a real evil but easily obviated by proper lining the frizzling of particles of organic matter of which we hear so much is if it really does occur highly advantageous seeing that it must destroy organic poison germs under some conditions the warm air of a room does deposit moisture on its cooler walls this happens in churches concert rooms etc when they are but occasionally used in winter time and mainly warmed by animal heat by congregational emanations of breath vapor and perspiration that is with warm air super saturated with vapor also when we have a sudden change from dry frosty weather to warm and humid then our walls may be streaming with condensed water such cases were probably in the mind of dr. Siemens when he spoke but they are quite different from stove heating or pipe heating which increase the vapor capacity of the heated air without supplying the demand it creates end of chapter 45 chapter 46 of science in short chapters this is a libervox recording all libervox recordings are in the public domain for more information or to volunteer please visit libervox.org recording by Tom Hirsch science in short chapters by W. Mathew Williams chapter 46 ventilation by open fireplaces the most stubborn of all errors are those which have been acquired by a sort of inheritance which have passed dogmatically from father to son or still worse from mother to daughter they may become superstitions without any theological character the idea that the weather changes with the moon that wind keeps off the rain are physical superstitions in all cases where they are blindly accepted and promulgated without any examination of evidence the idea that our open fireplaces are necessary for ventilation is one of these physical superstitions which is producing an incalculable amount of physical mischief throughout britain a little rational reflection on the natural and necessary movements of our household atmospheres demonstrates at once that this dogma is not only baseless but actually expresses the opposite of the truth i think i shall be able to show in what follows first that they do know useful ventilation and second that they render systematic and really effective ventilation practically impossible everybody knows that when air is heated it expands largely becomes lighter bulk for bulk than other air of lower temperature and therefore if two portions of air of unequal temperatures and free to move are in contact with each other the colder will flow under the warmer and push it upwards the latter postulate must be kept distinctly in view for the rising of warm air is too commonly regarded as due to some direct uprising activity or skyward affinity of its own instead of being understood as an indirect result of gravitation it is the downfalling of the cooler air that causes the uprising of the warmer now let us see what in accordance with the above stated simple laws must happen in an ordinary english apartment that is fitted as usual with one or more windows more or less leaky and one or more doors in like condition and a hole in the wall in which coal is burning in an iron cage immediately beneath the shaft that rises to the top of the house the fire hole itself having an extreme height of only 24 to 30 inches above the floor all the chimney above this height being entirely closed i find by measurement that 24 inches is the usual height of the upper edge of the chimney opening of an ordinary register stove old farmhouse fireplaces are open to the mantelpiece now what happens when a heap of coal is burning in this hole some of the heat from 10 to 20 percent according to the construction of the grate is radiated into the room the rest is conveyed by an ascending current of air up the chimney as this ascending current is rendered visible by the smoke entangled with it no further demonstration of its existence is needed but how is it pushed up the chimney evidently by cooler air that flows into the room from somewhere in which cooler air must get under it in order to lift it in ordinary rooms this supply of air is entirely dependent upon their defective construction bad joinery it enters only by the crevices surrounding the ill-fitting windows and doors no specially designed opening being made for it usually the chief inlet is the space under the door through which pours a rivulet of cold air that spreads out as a lake upon the floor this may easily be proved by holding a lighted taper in front of the bottom door chink when the window and other door if any are closed and the fire is burning briskly at the same time more or less of cold air is poured in at the top and the side spaces of the door and through the window chinks the proportion of air entering by these depends upon the capacity of the bottom door chink if this is large enough it will do nearly all the work otherwise every other possible leakage including the keyhole contributes but what is the path of the air which enters by these higher level openings the answer to this is supplied at once by the fact that such air being colder than that of the room it must fall immediately it enters the rivulet under the door is thus supplemented by cascades pouring down from the top and sides of the door and the top and sides of the windows all being tributaries to the lake of cold air covering the floor the next question to be considered is what is the depth of this lake in this as in every other such accumulation of either air or water the level of the upper surface of the lake is determined by that of its outlet the outlet in this case is the chimney hole through which all the overflow pours upward and therefore the surface of the flowing stratum of cold air corresponds with the upper part of the chimney hole or of the register where register stoves are used below this level there is abundant ventilation above it there is none the cat that sits on the hearth rug has an abundant supply of fresh air and if we had tracheal breathing apertures all down the sides of our bodies as caterpillars have those on our lower extremities might enjoy the ventilation if we squatted on the ground like savages something might be said for the fire hole ventilator but as we are addicted to sitting on chairs that raise our breathing apparatus considerably above the level of the top of the register the maximum efficiency of the flow of cold air in the lake below is expressed by the prevalence of chill blames and rheumatism the atmosphere in which our heads are immersed is practically stagnant the radiations from the fire plus the animal heat from our bodies just warm it sufficiently to enable the cool entering air to push it upwards above the chimney outlet and the surface of the lower moving stratum and to keep it there in a condition of stagnation if anybody doubts the correctness of this description he has only to sit in an ordinary english room where a good fire is burning the doors and windows closed as usual and then to blow a cloud by means of pipe cigar or by burning brown paper or otherwise when the movements below and the stagnation above which i have described will be rendered visible if there is nobody moving about to stir the air and the experiment is fairly made the level of the cool lake below will be distinctly shown by the clearing away of the smoke up to the level of the top of the register opening towards which it may be seen to sweep above this the smoke reads will remain merely waving about with slight movements due to the small inequalities of temperature caused by the fraction of heat radiated into the room from the front of the fire these movements are chiefly developed near the door and windows where the above mentioned cascades are falling and against the walls and furniture where feeble convection currents are rising due to the radiant heat absorbed by their surfaces the stagnation is the most complete about the middle of the room where there is the greatest bulk of vacant airspace when the inlet under the door is of considerable dimensions there may be some escape of warmer upper air at the top of the windows if their fitting is correspondingly defective these however are mere accidents they are not a part of the wanted chimney hole ventilation but interferences with it there is another experiment that illustrates the absence of ventilation in such rooms where gas is burning it is that of suspending a canary in a cage near the roof but this is cruel it kills the bird it would be a more satisfactory experiment to substitute for the canary bird any wingless biped who after reading the above still maintains that our fire holes are effective ventilators not only are the fire holes worthless and mischievous ventilators themselves but they render efficient ventilation by any other means practically impossible the are not ventilator that we sometimes see applied to the upper part of chimneys is marred in its action by the greedy draft below the tall chimney shaft with a fire burning immediately below it dominates all the atmospheric movement in the house unless another and more powerful upcast shaft be somewhere else in communication with the apartments but in this case the original or ordinary chimney would be converted into a downcast shaft pouring air downwards into the room instead of carrying it away upwards I need not describe the sort of ventilation thus obtainable while the fire is burning and smoking effective sanitary ventilation should supply gentle and uniformly diffused currents of air of moderate and equal temperature throughout the house we talk a great deal about the climate here and the climate there and when we grow old and can afford it we move to Bournemouth, Torquay, Mentun, Nice, Algiers, etc for better climates forgetting all the while that the climate in which we practically live is not that out of doors but the indoor climate of our dwellings the which in properly constructed house may be regulated to correspond to that of any latitude we may choose I maintain that the very first step towards the best attainable approximation to this in our existing houses is to brick up cement up or otherwise completely stop up all our existing fire holes and abolish all our existing fires but what next the reply to this will be found in the next chapter end of chapter 46 recording by Tom Hirsch