 CHAPTER XXII The Development of the Edison Storage Battery It is more than a hundred years since the elementary principle of the storage battery, or the accumulator, was detected by a Frenchman named Gautreau. It is just fifty years since another Frenchman named Plante discovered that on taking two thin plates of sheet lead, immersing them in dilute sulfuric acid and passing an electric current through the cell, the combination exhibited the ability to give back part of the original charging current owing to the chemical changes and reactions set up. Plante coiled up his sheets into a very handy cell like a little roll of carpet or pastry, but the trouble was that the battery took a long time to form, one sheet becoming coated with lead peroxide and the other with finely divided or spongy metallic lead. They would receive current, then, even after a long period of inaction, furnish or return an electromotive force from 1.85 to 2.2 volts. This ability to store up electrical energy produced by dynamos in ours otherwise idle, whether driven by steam, wind, or water, was a distinct advance in the art. But the sensational step was taken about 1880 when fowr in France and brush in America broke away from the slow and weary process of forming the plates and hit on clever methods of furnishing them ready-made, so to speak, by dabbing red lead into lead-grid plates just as butter is spread on a slice of homemade bread. This brought the storage battery at once into use as a practical, manufactured piece of apparatus, and the world was captivated with the idea. The great English scientist Sir William Thompson went wild with enthusiasm when a fowr-a-box of electricity was brought over from Paris to him in 1881 containing a million foot-pounds of stored energy. His biographer, Dr. Sylvannis P. Thompson, describes him as lying ill in bed with a wounded leg and watching results with an incandescent lamp fastened to his bed-curtain by a safety pin and lit up by current from the little fowr-a-cell. Said Sir William, it is going to be a most valuable practical affair, as valuable as water cisterns to people whether they had or had not systems of water-pipes and water supply. Indeed, in one outburst of panagiric the shrewd physicist remarked that he saw in it a realization of the most ardently and increasingly felt scientific aspiration of his life, an aspiration which he hardly dared to expect or see realized. A little later, however, Sir William, always cautious and canny, began to discover the inherent defects of the primitive battery as to disintegration, inefficiency, costliness, etc., and though offered tempting inducements, declined to lend his name to its financial introduction. Nevertheless, he accepted the principle as valuable and put the battery to actual use. For many years after this episode, the modern lead-lead type of battery thus brought forward with so great a flourish of trumpets had a hard time of it. Edison's attitude toward it, even as a useful supplement to his lighting system, was always one of skepticism, and he remarked contemptuously that the best storage battery he knew was a ton of coal. The financial fortunes of the battery, on both sides of the Atlantic, was as varied and as disastrous as its industrial, but it did at last emerge and made good. By 1905 the production of lead-lead storage batteries in the United States alone had reached a value for the year of nearly three million dollars, and it has increased greatly since that time. The storage battery is now regarded as an important and indispensable adjunct in nearly all modern electric lighting and electric railway systems of any magnitude, and in 1909, in spite of its weight, it had found adoption in over 10,000 automobiles of the truck, delivery wagon, pleasure carriage, and runabout types in America. Edison watched closely in this earlier development for about fifteen years, not changing his mind as to what he regarded as the incurable defects of the lead-lead type, but coming gradually to the conclusion that if a storage battery of some other and better type could be brought forward it would fulfill all the early hopes, however extravagant, of such men as Kelvin, Sir William Thompson, and would become as necessary and as universal as the incandescent lamp or the electric motor. The beginning of the present century found him at this point of new departure. Generally speaking, non-technical and uninitiated persons have a tendency to regard an invention as being more or less the ultimate result of some happy inspiration, and indeed there is no doubt that such may be the fact in some instances. But in most cases the inventor has intentionally set out to accomplish a definite and desired result, mostly through the application of the known laws of the art in which he happens to be working. It is rarely, however, that a man will start out deliberately, as Edison did, to evolve a radically new type of such intricate device as the storage battery, with only a meager clue and a vague starting point. In view of the successful outcome of the problem, which in 1900 he undertook to solve, it will be interesting to review his mental attitude at that period. It has already been noted at the end of a previous chapter that on closing the magnetic iron ore concentrating plant at Edison, New Jersey, he resolved to work on a new type of storage battery. It was about this time that in the course of a conversation with Mr. R. H. Beech, then of the Street Railway Department of the General Electric Company, he said, Beech, I don't think nature would be so unkind as to withhold the secret of a good storage battery if a real earnest hunt for it is made. I'm going to hunt. Frequently Edison has been asked what he considers the secret of achievement. To this query he has invariably replied, hard work based on hard thinking. The laboratory records bear the fullest witness that he has consistently followed out this prescription to the utmost. The perfection of all his great inventions has been signalized by patient, persistent and incessant effort, which recognizing nothing short of success has resulted in the ultimate accomplishment of his ideas. Like and hopeful to a high degree Edison has the happy faculty of beginning the day as open minded as a child, yesterday's disappointments and failures discarded and discounted by the alluring possibilities of tomorrow. Of all of his inventions it is doubtful whether any one of them has called forth more original thought, work, perseverance, ingenuity and monumental patience than the one we are now dealing with. One of his associates, who has been through the many years of the storage battery drudgery with him, said, if Edison's experiments, investigations and work on this storage battery were all that he had ever done, I should say that he was not only a notable inventor, but also a great man. It's almost impossible to appreciate the enormous difficulties that have been overcome. From a beginning, which was practically made in the dark, it was not until he had completed more than ten thousand experiments that he obtained any positive preliminary results whatever. Through all this vast amount of research there had been no previous signs of the electrical action he was looking for. These experiments had extended over many months of constant work by day and night. But there was no breakdown of Edison's faith in ultimate success, no diminution of his sanguine and confident expectations. The failure of an experiment simply meant to him that he had found something else that would not work, thus bringing the impossible goal a little nearer by a process of painstaking elimination. Now however, after these many months of arduous toil, in which he had examined and tested practically all the known elements in numerous chemical combinations, the electric action he sought for had been obtained, thus affording him the first inkling of the secret that he had industriously tried to rest from nature. It should be borne in mind that from the very outset Edison had disdained any intention of following in the only tracts then known by employing lead and sulfuric acid as the components of a successful storage battery. Impressed with what he considered the serious inherent defects of batteries made of these materials, and the tremendously complex nature of the chemical reactions taking place in all types of such cells, he determined boldly at the start that he would devise a battery without lead and one in which an alkaline solution could be used, a form which would, he firmly believed, be inherently less subject to decay and dissolution than the standard type, which after many setbacks had finally won its way to an annual production of many thousands of cells worth millions of dollars. Two or three thousand of the first experiments followed the lines of his well-known primary battery in the attempted employment of copper oxide as an element in a new type of storage cell. But its use offered no advantages, and the hunt was continued in other directions and pursued until Edison satisfied himself by a vast number of experiments that nickel and iron possessed the desirable qualifications he was in search of. This immense amount of investigation which had consumed so many months of time and which had culminated in the discovery of a series of reactions between nickel and iron that bore great promise brought Edison merely within sight of a strange and hitherto unexplored country. Slowly but surely the results of the last few thousands of his preliminary experiments had pointed inevitably to a new and fruitful region ahead. He had discovered the hidden passage and held the clue which he had so industriously sought. And now, having outlined a definite path, Edison was all afire to push ahead vigorously in order that he might enter in and possess the land. It is a trite saying that history repeats itself, and certainly no axiom carries more truth than this one applied to the history of each of Edison's important inventions. The development of the storage battery has been no exception, indeed, far from otherwise, for in the ten years that have elapsed since the time he set himself and his mechanics, chemists, machinists, and experimenters at work to develop a practical commercial cell, the old story of incessant and persistent efforts so manifest in the working out of other inventions was fully repeated. Very soon after he had decided upon the use of nickel and iron as the elemental metals for his storage battery, Edison established a chemical plant at Silver Lake, New Jersey, a few miles from the Orange Laboratory on land purchased some time previously. This place was the scene of further experiments to develop the various chemical forms of nickel and iron, and to determine by tests what would be best adapted for use in cells manufactured on a commercial scale. With a little handful of selected experimenters gathered about him, Edison settled down to one of his characteristic struggles for supremacy. To some extent it was a revival of the old Menlo Park days, or rather nights. Some of these who had worked on the preliminary experiments, with the addition of a few newcomers, toiled together regardless of passing time and often under most discouraging circumstances. But with that remarkable esprit decor that has ever marked Edison's relations with his co-workers, and that has contributed so largely to the successful carrying out of his ideas. The group that took part in these early years of Edison's arduous labors included his old time assistant, Fred Ott, together with his chemist, J. W. Alsworth, as well as E. J. Ross Jr., W. E. Holland, and Ralph Abergast, and a little later W. G. B., all of whom have grown up with the battery and still devote their energies to its commercial development. One of these workers, relating the strenuous experiences of these few years says, it was hard work and long hours, but still there were some things that made life pleasant. One of them was the supper-hour we enjoyed, when we worked nights. Mr. Edison would have supper sent in about midnight, and we all sat down together, including himself. Work was forgotten for the time, and all hands were ready for fun. I have very pleasant recollections of Mr. Edison at these times. He would always relax and help to make a good time. And then on some occasions I have seen him fairly overflow with animal spirits, just like a boy let out from school. After the supper-hour was over, however, he again became a serious energetic inventor, deeply immersed in the work at hand. He was very fond of telling and hearing stories, and always appreciated a joke. I remember one that he liked to get off on us once in a while. Our lighting plant was in duplicate, and about twelve-thirty, or one o'clock in the morning, at the close of the supper-hour, a change would be made from one plant to the other, involving the gradual extinction of the electric lights, and there slowly coming up to candle-power again. The whole change requiring probably about thirty seconds. Sometimes, as this was taking place, Edison would fold his hands, compose himself as if he were in sound sleep, and when the lights were full again would apparently wake up with the remark, well, boys, we've had a fine rest. Now let's pitch in to work again. Another interesting and amusing reminiscence of this period of activity has been gathered from another of the family of experimenters. Sometimes, when Mr. Edison had been working long hours, he would want to have a short sleep. It was one of the funniest things I ever witnessed to see him crawl into an ordinary roll-top desk, curl up, and take a nap. If there was a sight that was still more funny, it was to see him turn over on his other side, all the time remaining in the desk. He would use several volumes of Watt's dictionary of chemistry for a pillow, and we fellows used to say that he absorbed the contents during his sleep, judging from the flow of new ideas he had on waking. Such incidents as these serve merely to illustrate the lighter moments that stand out in relief against the more somber background of the strenuous years, four of all the absorbingly busy periods of Edison's inventive life. The first five years of the storage battery era was one of the busiest of them all. It was not that there remained any basic principle to be discovered or simplified, for that had already been done. But it was in the effort to carry these principles into practice that there arose the numerous difficulties that at times seemed insurmountable. But according to another co-worker, Edison seemed pleased when he used to run up against a serious difficulty. It would seem to stiffen his backbone and make him more prolific of new ideas. For a time I thought I was foolish to imagine such a thing, but I could never get away from the impression that he really appeared happy when he ran up against a serious snag. That was in my green days, and I soon learned that the failure of an experiment never discourages him unless it is by reason of the carelessness of the man making it. Then Edison gets disgusted. If it fails on its merits he doesn't worry or fret about it, but on the contrary regards it as a useful fact learned, remains cheerful and tries something else. I have known him to reverse an unsuccessful experiment and come out all right. To follow Edison's trail in detail through the innumerable twists and turns of his experimentation and research on the storage battery during the past ten years, it would not be in keeping with the scope of this narrative nor would it serve any useful purpose. Besides, such details would fill a big volume. The narrative, however, would not be complete without some mention of the general outline of his work and reference may be made briefly to a few of the chief items. Unless the reader think that the word innumerable may have been carelessly or hastily used above, we would quote the reply of one of the laboratory assistants when asked how many experiments had been made on the Edison storage battery since the year 1900. Goodness only knows. We used to number our experiments consecutively from one to ten thousand, and when we got up to ten thousand we turned back to one and ran up to ten thousand again and so on. We ran through several series. I don't know how many, and have lost track of them now, but it was not far from fifty thousand. From the very first Edison's broad idea of his storage battery was to make perforated metallic containers having the active materials packed therein. Nickel hydrate for the positive and iron oxide for the negative plate. This plan has been adhered to throughout and has found its consumption in the present form of the completed commercial cell, but in the middle ground which stands between the early crude beginnings and the perfected type of today there lies a world of original thought, patient plotting, and achievement. The first necessity was naturally to obtain the best and purest compounds for active materials. Edison found that comparatively little was known by manufacturing chemists about nickel and iron oxides of the high-grade impurity he required. Hence it became necessary for him to establish his own chemical works and put them in charge of men specifically trained by himself with whom he worked. This was the plant at Silver Lake above referred to. Here, for several years, there was ceaseless activity in the preparation of these chemical compounds by every imaginable process and subsequent testing. Edison's chief chemist says, �We left no stone unturned to find a way of making those chemicals so that they would give the highest results. We carried on the experiments with the two chemicals together. Sometimes the nickel would be ahead in the tests, and then again it would fall behind. To stimulate us to greater improvement, Edison hung up a card which showed the results of tests in milliampere hours given by the experimental elements as we tried them with the various grades of nickel and iron we had made.� This stirred up a great deal of ambition among the boys to push the figures up. Some of our earliest tests showed around three hundred, but as we improved the material they gradually crept up to over five hundred. Just about that time Edison had made a trip to Canada, and when he came back we had made such good progress that the figures had crept up to about one thousand. I well remember how greatly he was pleased. In speaking of the development of the negative element of the battery, Mr. Alsworth says, �In a like manner the iron element had to be developed and improved, and finally the iron element, which had generally enjoyed superiority in capacity over its companion, the nickel element, had to go in training in order to retain its lead, which was imperative in order to produce a uniform and consistent voltage curve. In talking with me one day about the difficulties under which we were working, and contrasting them with the phonographic experimentation, Edison said, �In phonographic work we can use our ears and our eyes, aided with powerful microscopes, but in the battery our difficulties cannot be seen or heard, but must be observed by our mind�s eye. And by reason of the employment of such vision in the past, Edison is now able to see quite clearly through the forest of difficulties, after eliminating them one by one. �The size and shape of the containing pockets in the battery plates or elements and the degree of their preparation were matters that received many years of close study and experiment. Indeed, there is still today constant work expended on their perfection, although their present general form was decided upon several years ago. �The mechanical construction of the battery as a whole, in its present form, compels instant admiration on account of its beauty and completeness. Mr. Edison has spared neither thought, ingenuity, labor, nor money in the effort to make it the most complete and efficient storage cell obtainable, and the results show that his skill, judgment and foresight have lost nothing of the power that laid the foundation of and built up other great arts at each earlier stage of his career. �Among the complex and numerous problems that presented themselves in the evolution of the battery was the concerning and internal conductivity of the positive unit. The nickel hydrate was a poor electrical conductor, and although a metallic nickel pocket might be filled with it, there would not be the desired electrical action unless a conducting substance were mixed with it, and so incorporated packed that there would be a good electrical contact throughout. This proved to be a most naughty and intricate puzzle, tricky and evasive, always leading on and promising something, and at the last slipping away leaving the work undone. Edison's remarkable patience and persistence in dealing with this trying problem, and in finally solving it successfully, won for him more than ordinary admiration from his associates. One of them, in speaking of the seemingly interminable experiments to overcome this trouble, said, �I guess that questions of conductivity of the positive pocket brought lots of gray hairs to his head. I never dreamed a man could have such patience and perseverance. Any other man than Edison would have given the whole thing up a thousand times, but not he. Things looked awfully blue to the whole bunch of us many a time, but he was always hopeful. I remember one time things looked so dark to me that I had just about made up my mind to throw up my job. But some good turn came just then, and I didn't. Now I'm glad I held on, for we've got a great future.� The difficulty of obtaining good electrical contact in the positive element was indeed Edison's chief trouble for many years. After a great amount of work and experimentation, he decided upon a certain form of graphite which seemed to be suitable for the purpose, and then proceeded to the commercial manufacture of the battery at a special factory in Glenridge, New Jersey, installed for the purpose. There was no lack of buyers, but on the contrary, the factory was unable to turn out batteries enough. The newspapers had previously published articles showing the unusual capacity and performance of the battery, and public interest had thus been greatly awakened. Notwithstanding, the establishment of a regular routine of manufacture and sale, Edison did not cease to experiment for improvement. Although the graphite apparently did the work desired of it, he was not altogether satisfied with its performance, and made extended trials of other substances. But at that time found nothing that on the whole served the purpose better. Continuous tests of the commercial cells were carried out at the laboratory, as well as more practical and heavy tests in automobiles, which were constantly kept running around the adjoining country over all kinds of roads. All these tests were very closely watched by Edison, who demanded rigorously that the various trials of the battery should be carried on with all strenuousness so as to get the utmost results and develop any possible weakness. So insistent was he on this, that if any automobile should run several days without bursting a tire or breaking some parts of the machine, he would accuse the chauffeur of picking out easy roads. After these tests had been going on for some time, and some thousands of cells had been sold and were giving satisfactory results to the purchasers, the test sheets and experience gathered from various sources pointed to the fact that occasionally a cell here and there would show up as being short in capacity. In as much as the factory processes were very exact and carefully guarded, and every cell was made as uniform as human skill and care could provide, there thus arose a serious problem. Edison concentrated his powers on the investigation of this trouble, and found that the chief cause lay in the graphite. Some other minor matters also attracted his attention. What to do was the important question that confronted him. To shut down the factory meant great loss and apparent failure. He realized this fully, but he also knew that to go on would simply be to increase the number of defective batteries in circulation, which would ultimately result in a permanent closure and real failure. Hence he took the course which one would expect of Edison's common sense and directness of action. He was not satisfied that the battery was a complete success, so he shut down and went to experimenting once more. And then, says one of the laboratory men, we started on another series of record-breaking experiments that lasted over five years. I might almost say heartbreaking, too, for all of the elusive disappointing things one ever hunted for that was the worst. But secrets have to be long-winded and roost high if they want to get away when the old man goes hunting for them. He doesn't get mad when he misses them, but just keeps on smiling and firing and usually brings them into camp. That's what he did on the battery, for after a whole lot of work he perfected the nickel flake idea and process, besides making the great improvement of using tubes instead of flat pockets for the positive. He also added a minor improvement here and there, and now we have a finer battery than we ever expected. In the interim, while the experimentation of these last five years was in progress, many customers who purchased batteries of the original type came knocking at the door with orders in their hands for additional outfits, wherewith to equip more wagons and trucks. Edison expressed his regrets, but said he was not satisfied with the old cells and was engaged in improving them. To which the customers replied that they were entirely satisfied and ready and willing to pay for more batteries of the same kind. But Edison could not be moved from his determination, although considerable pressure was at time brought to bear to sway his decision. Experiment was continued beyond the point of per adventure, and after some new machinery had been built the manufacturer of the new type of cell was begun in the early summer of 1909, and at the present writing is being extended as fast as the necessary additional machinery can be made. The product is shipped out as soon as it is completed. The nickel flake, which is Edison's ingenious solution to the conductivity problem, is of itself a most interesting product, intensely practical in its application and fascinating in its manufacture. The flake of nickel is obtained by electroplating upon a metallic cylinder alternate layers of copper and nickel, one hundred of each after which the combined sheet is stripped from the cylinder. So thin are the layers that this sheet is only about the thickness of a visiting card, and yet it is composed of two hundred layers of metal. The sheet is cut into tiny squares, each about one sixteenth of an inch, and these squares are put into a bath where the copper is dissolved out. This releases the layers of nickel so that each of these small squares becomes one hundred tiny sheets or flakes of pure metallic nickel so thin that when they are dried they will float in the air like fissile down. In their application to the manufacturer of batteries, the flakes are used through the medium of a special machine so arranged that small charges of nickel hydrate and nickel flakes are alternately fed into the pockets intended for positives and tamped down with a pressure equal to about four tons per square inch. This ensures complete and perfect contact and subsequent electrical conductivity throughout the entire unit. The development of the nickel flake contains in itself a history of patient investigation, labor and achievement, but we have not space for it nor for tracing the great work that has been done in developing and perfecting the numerous other parts and adjuncts of this remarkable battery. Suffice it to say that when Edison went boldly out into new territory after something entirely unknown he was quite prepared for hard work and exploration. He encountered both in unstinted measure but kept going forward until after long travel he had found all that he had expected and accomplished something more besides. Nature did respond to his whole hearted appeal and by the time the hunt was ended revealed a good storage battery of entirely new type. Edison not only recognized and took advantage of the principles he had discovered but in adapting them for commercial use developed most ingenious processes and mechanical appliances for carrying his discoveries into practical effect. Indeed it may be said that the invention of an enormous variety of new machines and mechanical appliances rendered necessary by each change during the various stages of development of the battery from first to last stands as the lasting tribute to the range and versatility of his powers. It is not within the scope of this narrative to enter into any description of the relative merits of the Edison storage battery, that being the province of a commercial catalog. It does however seem entirely allowable to say that while at the present writing the tests that have been made extend over a few years only their results and the intrinsic value of this characteristic Edison invention are of such a substantial nature as to point to the inevitable growth of another great industry arising from its manufacturer and to its widespread application to many uses. The principle use that Edison has had in mind for his battery is transportation of freight and passengers by truck automobile and streetcar. The greatly increased capacity in proportion to weight of the Edison cell makes it particularly adaptable for this class of work on account of the much greater radius of travel that is possible by its use. The latter point of advantage is the one that appeals most to the Automobilist as he is thus enabled to travel it is asserted more than three times further than ever before on a single charge of the battery. Edison believes that there are more important advantages possible in the employment of his storage battery for streetcar propulsion. Under the present system of operation a plant furnishing the electric power for street railways must be large enough to supply current for the maximum load during rush hours although much of the machinery may be lying idle and unproductive in the hours of minimum load. By the use of storage battery cars this immense and uneconomical maximum investment in plant can be cut down to proportions of true commercial economy as the charging of the batteries can be conducted at a uniform rate with a reasonable expenditure for generating machinery. Not only this but each car becomes an independently moving unit not subject to delay by reason of a general breakdown of the power plant or of the line. In addition to these advantages the streets would be freed from their burden of trolley wires or conduits. To put his ideas into practice Edison built a short railway line at the Orange Works in the winter of 1909-1910 and in cooperation with Mr. R. H. Beach constructed a special type of streetcar and equipped it with motor, storage battery, and other necessary operating devices. This car was subsequently put upon the streetcar lines in New York City and demonstrated its efficiency so completely that it was purchased by one of the streetcar companies which has since ordered additional cars for its lines. The demonstration of this initial car has been watched with interest by many railroad officials and its performance has been of so successful a nature that at the present writing the summer of 1910 it has been necessary to organize and equip a preliminary factory in which to construct many other cars of a similar type that have been ordered by other street railway companies. This enterprise will be conducted by a corporation which has been specially organized for the purpose. Thus there has been initiated the development of a new and important industry whose possible ultimate proportions are beyond the range of present calculation. Extensive as this industry may become however Edison is firmly convinced that the greatest field for his storage battery lies in its adaptation to commercial trucking and hauling and to pleasure vehicles in comparison with which the streetcar business even with its great possibilities will not amount to more than one percent. Edison has pithily summed up his work and his views in an article on the tomorrows of electricity and invention in popular electricity for June 1910 in which he says, for years past I have been trying to perfect a storage battery and have now rendered it entirely suitable to automobile and other work. There is absolutely no reason why horses should be allowed within city limits, for between the gasoline and the electric car no room is left for them. They are not needed. The cow and the pig have gone. The horse is still more undesirable. A higher public ideal of health and cleanliness is working towards such banishment very swiftly. And then we shall have decent streets instead of stables made out of strips of cobblestone bordered by sidewalks. The worst use of money is to make a fine thoroughfare and then turn it over to horses. Besides that, the change will put the humane societies out of business. Many people now charge their own batteries because of lack of facilities. But I believe central stations will find in this work very soon the largest part of their load. The New York Edison Company, or the Chicago Edison Company, should have as much current going out for storage batteries as for power motors, and it will be so some near day. Edison, His Life and Inventions, by Frank Lewis Dyer and Thomas Comerford Martin, Chapter 23, Miscellaneous Inventions It has been the endeavor in this narrative to group Edison's inventions and patents so that his work in the different fields can be studied independently and separately. The history of his career has therefore fallen naturally into a series of chapters, each aiming to describe some particular development or art. And, in a way, the plan has been helpful to the writers while probably useful to the readers. It happens, however, that the process has left a vast mass of discovery and invention wholly untouched and relegates to a concluding brief chapter some of the most interesting episodes of A Fruitful Life. Anyone who will turn to the list of Edison patents at the end of the book will find a large number of things of which not even casual mention has been made, but which at the time occupied no small amount of the inventor's time and attention, and many of which are now part and parcel of modern civilization. Edison has, indeed, touched nothing that he did not in some way improve. As Thoreau said, The laws of the universe are not indifferent, but are forever on the side of the most sensitive. And there never was anyone more sensitive to the defects of every art and appliance, nor anyone more active in applying the law of evolution. It is perhaps this many-sidedness of Edison that has impressed the multitude, and that in the popular vote taken a couple of years ago by the New York Herald placed his name at the head of the list of ten greatest living Americans. It is curious and pertinent to note that a similar plebiscite taken by a technical journal among its expert readers had exactly the same result. Evidently, the public does not agree with the opinion expressed by the eccentric artist Blake in his Marriage of Heaven and Hell when he said, improvement makes strange roads, but the crooked roads without improvements are roads of genius. The product of Edison's brain may be divided into three classes. The first embraces such arts and industries or such apparatus as have already been treated. The second includes devices like the Tessimeter, Phenometer, Odorscope, etc., and others now to be noted. The third embraces a number of projected inventions, partially completed investigations, inventions in use but not patented, and a great many caveats filed in the patent office at various times during the last 40 years for the purpose of protecting his ideas pending their contemplated realization in practice. These caveats served their purpose thoroughly in many instances, but there have remained a great variety of projects upon which no definite action was ever taken. One ought to add the contents of an unfinished piece of extraordinary fiction based wholly on new inventions and devices utterly unknown to mankind. Someday the novel may be finished, but Edison has no inclination to go back to it, and says he cannot understand how any man is able to make a speech or write a book, for he simply can't do it. After what has been said in previous chapters, it will not seem so strange that Edison should have hundreds of dormant inventions on his hands. There are human limitations even for such a tireless worker as he is. While the preparation of data for this chapter was going on, one of the writers in discussing with him the vast array of unexploited things said, Don't you feel a sense of regret in being obliged to leave so many things uncompleted? To which he replied, What's the use? One lifetime is too short, and I am busy every day improving essential parts of my established industries. It must suffice to speak briefly of a few leading inventions that have been worked out, and to dismiss with scant mention all the rest, taking just a few items as typical and suggestive, especially when Edison had can himself be quoted as to them. Incidentally, it may be noted that things not words are referred to, for Edison, in addition to inventing the apparatus, has often had to coin the word to describe it. A large number of the words and phrases in modern electrical parlance owe their origin to him. Even the call word of the telephone, hello, sent tingling over the wire a few million times daily, was taken from Menlo Park by men installing telephones in different parts of the world, men who had just learned it at the laboratory, and thus made it a universal sesame for a telephonic conversation. It is hard to determine where to begin with Edison's miscellaneous inventions, but perhaps telegraphy has the right of line, and Edison's work in that field puts him abreast of the latest wireless developments that fill the world with wonder. I perfected a system of train telegraphy between stations and trains in motion, whereby messages could be sent from the moving train to the central office, and this was the forerunner of wireless telegraphy. This system was used for a number of years on the Lehigh Valley Railroad, on their construction trains. The electric wave passed from a piece of metal on top of the car across the air to the telegraph wires, and then proceeded to the dispatcher's office. In my first experiments with this system I tried it on the Staten Island Railroad, and employed an operator named King to do the experimenting. He reported results every day and received instructions by mail, but for some reason he could send messages all right when the train went in one direction but could not make it go in the contrary direction. I made suggestions of every kind to get around this phenomenon. Finally I telegraphed King to find out if he had any suggestions himself, and I received a reply that the only way he could propose to get around the difficulty was to put the island on a pivot so it could be turned around. I found the trouble finally, and the practical introduction on the Lehigh Valley Road was the result. The system was sold to a very wealthy man and he would never sell any rights or answer letters. He became a spiritualist subsequently, which probably explains it. It is interesting to note that Edison became greatly interested in the later developments by Marconi and is an admiring friend and advisor of that well-known inventor. The earlier experiments with wireless telegraphy at Menlo Park were made at a time when Edison was greatly occupied with his electric light interests, and it was not until the beginning of 1886 that he was able to spare the time to make a public demonstration of the system as applied to moving trains. Ezra T. Gilliland of Boston had become associated with him in his experiments, and they took out several joint patents subsequently. The first practical use of the system took place on a 13-mile stretch of the Staten Island Railroad with the results mentioned by Edison above. A little later, Edison and Gilliland joined forces with Lucius J. Phelps, another investigator, who had been experimenting along the same lines and had taken out several patents. The various interests were combined in a corporation under whose auspices the system was installed on the Lehigh Valley Railroad, where it was used for several years. The official demonstration trip on this road took place on October 6, 1887, on a six-car train running to Easton, Pennsylvania, a distance of 54 miles. A great many telegrams were sent and received while the train was at full speed, including a dispatch to the Cable King, John Pender, London, England, and a reply from him. Broadly described in Outline, the system consisted of an induction circuit obtained by laying strips of tin along the top or roof of a railway car and the installation of a special telegraph line running parallel with the track and strong on poles of only medium height. The train and also each signalling station were equipped with regulation telegraphic apparatus such as battery, key, relay, and sounder, together with induction coil and condenser. In addition, there was a transmitting device in the shape of a musical read or buzzer. In practice, this buzzer was continuously operated at high speed by a battery. Its vibrations were broken by means of a key into long and short periods, representing Morse characters, which were transmitted inductively from the train circuit to the pole line, or vice versa, and received by the operator at the other end through a high-resistance telephone receiver inserted in the secondary circuit of the induction coil. Although the space between the cars and the pole line was probably not more than about fifty feet, it is interesting to note that in Edison's early experiments at Menlo Park, he succeeded in transmitting messages through the air at a distance of five hundred eighty feet. Speaking of this and of his other experiments with induction telegraphy by means of kites, communicating from one to the other and thus from the kites to instruments on the earth, Edison said recently, we only transmitted about two and one half miles through the kites. What has always puzzled me sense is that I did not think of using the results of my experiments on aetheric force that I made in 1875. I have never been able to understand how I came to overlook them. If I had made use of my own work, I should have had long distance wireless telegraphy. In one of the appendices to this book is given a brief technical account of Edison's investigations of the phenomena which lie at the root of modern wireless or space telegraphy, and the attention of the reader is directed particularly to the description and quotations there from the famous notebooks of Edison's experiments in regard to what he called aetheric force. It will be seen that as early as 1875 Edison detected and studied certain phenomena, i.e. the production of electrical effects in non-closed circuits, which for a time made him think he was on the trail of a new force, as there was no plausible explanation for them by the then known laws of electricity and magnetism. Later came the magnificent work of Hertz identifying the phenomena as electromagnetic waves in the aether and developing a new world of theory and science based upon them and their production by disruptive discharges. Edison's assertions were treated with skepticism by the scientific world, which was not then ready for the discovery and not sufficiently furnished with corroborative data. It is singular to say the least to note how Edison's experiments paralleled and proved in advance those that came later. And even his apparatus such as the dark box for making the tiny sparks visible, as the waves impinged on the receiver, bears close analogy with similar apparatus employed by Hertz. Indeed, as Edison sent the dark box apparatus to the Paris Exposition in 1881 and let Bachelor repeat there the puzzling experiments, it seems by no means unlikely that either directly or on the report of some friend, Hertz may thus have received from Edison a most valuable suggestion, the inventor aiding the physicist in opening up a wonderful new realm. In this connection, indeed, it is very interesting to quote two great authorities. In May 1889 at a meeting of the institution of electrical engineers in London, Doctor, now Sir, Oliver Lodge remarked in a discussion on a paper of his own on lightning conductors embracing the Hertzian waves in his treatment. Many of the effects I have shown sparks in unsuspected places and other things have been observed before. Henry observed things of the kind and Edison noticed some curious phenomena and said it was not electricity but etheric force that caused these sparks, and the matter was rather poo-pooed. It was a small part of this very thing, only the time was not ripe, theoretical knowledge was not ready for it. Again in his signaling without wires, in giving the history of the Cohera principle, Lodge remarks, sparks identical in all respects with those discovered by Hertz had been seen in recent times both by Edison and by Sylvanus Thompson being styled etheric force by the former, but their theoretic significance had not been perceived and they were somewhat skeptically regarded. During the same discussion in London in 1889, Sir William Thompson, Lord Calvin, after citing some experiments by Faraday with his insulated cage at the Royal Institution, said, His Faraday's attention was not directed to look for Hertz sparks, or probably he might have found them in the interior. Edison seems to have noticed something of the kind in what he called etheric force. His name etheric may thirteen years ago have seemed to many people absurd, but now we are all beginning to call these inductive phenomena etheric, with which testimony from the Great Calvin as to his priority in determining the vital fact, and with the evidence that is early as 1875, he built apparatus that demonstrated the fact, Edison is probably quite content. It should perhaps be noted at this point that a curious effect observed at the laboratory was shown in connection with Edison lamps at the Philadelphia exhibition of 1884. It became known in scientific parlance as the Edison effect, showing a curious current condition or discharge in the vacuum of the bulb. It has since been employed by Fleming in England and de Forest in this country, and others as the basis for wireless telegraph apparatus. It is in reality a minute rectifier of alternating current and analogous to those which have been since been made on a large scale. When Röntgen came forward with his discovery of the new X-ray in 1895, Edison was ready for it and took up experimentation with it on a large scale. Some of his work being recorded in an article in the Century magazine of May 1896, where a great deal of data may be found. Edison says with regard to this work, when the X-ray came up, I made the first fluoroscope using tongue state of calcium. I also found that this tongue state could be put into a vacuum chamber of glass and fused to the inner walls of the chamber, and if the X-ray electrodes were let into the glass chamber and a proper vacuum was attained, you could get a fluorescent lamp of several candle power. I started in to make a number of these lamps, but I soon found that the X-ray had affected poisonously my assistant, Mr. Dali, so that his hair came out and his flesh commenced to ulcerate. I then concluded it would not do, and that it would not be a very popular kind of light, so I dropped it. At the time I selected tongue state of calcium because it was so fluorescent. I set four men to making all kinds of chemical combinations and thus collected upward of 8,000 different crystals of various chemical combinations, discovering several hundred different substances which would fluoresce to the X-ray. So far little had come of X-ray work, but it added another letter to the scientific alphabet. I don't know anything about radium, and I have lots of company. The electrical engineer of June 3rd, 1896, contains a photograph of Mr. Edison taken by the light of one of his fluorescent lamps. The same journal, in its issue of April 1st, 1896, shows an Edison fluoroscope in use by an observer in the now familiar and universal form somewhat like a stereoscope. This apparatus, as invented by Edison, consists of a flaring box curved at one end to fit closely over the forehead and eyes, while the other end of the box is closed by a pasteboard cover. On the inside of this is spread a layer of tongue state of calcium. By placing the object to be observed, such as the hand between the vacuum tube and the fluorescent screen, the shadow is formed on the screen and can be observed at leisure. The apparatus has proved invaluable in surgery and has become an accepted part of the equipment of modern surgery. In 1896, at the electrical exhibition in the Grand Central Palace, New York City, given under the auspices of the National Electric Light Association, thousands and thousands of persons with the use of this apparatus in Edison's personal exhibit were enabled to see their own bones, and the resultant public sensation was great. Mr. Mallory tells a characteristic story of Edison's own share in the memorable exhibit. The exhibit was announced for opening on Monday. On the preceding Friday, all the apparatus, which included a large induction coil, was shipped from Orange to New York, and on Saturday afternoon Edison, accompanied by Fred Ott, one of his assistants, and myself, went over to install it so as to have it ready for Monday morning. Had everything been normal, a few hours would have sufficed for completion of the work. But on coming to test the big coil, it was found to be absolutely out of commission, having been so seriously injured as to necessitate its entire rewinding. It being summertime, all the machine shops were closed until Monday morning, and there were several miles of wire to be wound on the coil. Edison would not consider a postponement of the exhibition, so there was nothing to do but go to work and wind it by hand. We managed to find a lathe, but there was no power, so each of us, including Edison, took turns revolving the lathe by pulling on the belt, while the other two attended to the winding of the wire. We worked continuously all through that Saturday night and all day Sunday until evening when we finished the job. I don't remember ever being conscious of more muscles in my life. I guess Edison was tired also, but he took it very philosophically. This was apparently the first public demonstration of the x-ray to the American people. Edison's ore separation work has been already fully described, but the story would hardly be complete without a reference to a similar work in gold extraction dating back to the Menlo Park days. I got up a method, says Edison, of separating placer gold by a dry process, in which I could work economically or as lean as five cents of gold to the cubic yard. I had several carloads of different placer sands sent to me and proved I could do it. Some parties, hearing I had succeeded in doing such a thing, went to work and got hold of what was known as the Ortiz Mine Grant, twelve miles from Santa Fe, New Mexico. This mine, according to the reports of several mining engineers made in the last forty years, was considered one of the richest placer deposits in the United States, and various schemes had been put forward to bring water from the mountains forty miles away to work those immense beds. The reports stated that the Mexicans had been panning gold for a hundred years out of these deposits. These parties now made arrangements with the stockholders or owners of the grant, and with me, to work the deposits by my process. As I had had some previous experience with the statements of mining men, I concluded I would just send down a small plant and prospect the field before putting up a large one. This I did and I sent two of my assistants whom I could trust down to this place to erect the plant, and started to sink shafts fifty feet deep all over the area. We soon learned that the rich gravel, instead of being spread over an area of three by seven miles, and rich from the grass roots down, was spread over a space of about twenty-five acres, and that even this did not average more than ten cents to the cubic yard. The whole placer would not give more than one and one-quarter cents per cubic yard. As my business arrangements had not been very perfectly made, I lost the usual amount. Going to another extreme, we find Edison grappling with one of the biggest problems known to the authorities of New York, the disposal of its heavy snows. It is needless to say that witnessing the ordinary slow and costly procedure would put Edison on his metal. One time when they had a snow blockade in New York, I started to build a machine with bachelor. A big truck with a steam engine and compressor on it. We would run along the street, gather all the snow up in front of us, pass it into the compressor, and deliver little blocks of ice behind us in the gutter, taking one tent the room of the snow, and not inconveniencing anybody. We could thus take care of a snowstorm by diminishing the bulk of material to be handled. The preliminary experiment we made was dropped because we went into other things. The machine would go as fast as a horse could walk. Edison has always taken a keen interest in aerial flight, and has also experimented with aeroplanes, his preference inclining to the helicopter type, as noted in the newspapers and periodicals from time to time. The following statement from him refers to a type of airplane of great novelty and ingenuity. James Gordon Bennett came to me and asked that I try some primary experiments to see if aerial navigation was feasible with heavier than air or machines. I got up a motor and put it on the scales and tried a large number of different things and contrivances connected to the motor to see how it would lighten itself on the scales. I got some data and made up my mind that what was needed was a very powerful engine for its weight in small compass, so I conceived of an engine employing gun cotton. I took a lot of ticker paper tape, turned it into gun cotton, and got up an engine with an arrangement whereby I could feed this gun cotton strip into the cylinder and explode it inside electrically. The feed took place between two copper rolls. The copper kept the temperature down so that it could only explode up to the point where it was in contact with the feed rolls. It worked pretty well, but once the feed roll didn't save it and the flame went through and exploded the whole roll and kicked up such a bad explosion I abandoned it. But the idea might be made to work. Turning from the air to the earth, it is interesting to note that the introduction of the underground Edison system in New York made an appeal to inventive ingenuity and that one of the difficulties was met as follows. When we first put the Pearl Street station in operation in New York, we had cast iron junction boxes at the intersections of all the streets. One night, or about two o'clock in the morning, a policeman came in and said that something had exploded at the corner of William and Nassau streets. I happened to be in the station and went out to see what it was. I found that the cover of the manhole, weighing about two hundred pounds, had entirely disappeared, but everything inside was intact. It had even stripped some of the threads of the bolts, and we could never find that cover. I concluded it was either a leakage of gas into the manhole, or else the acid used in pickling the casting had given off hydrogen and the air had leaked in, making an explosive mixture. As this was a pretty serious problem, and as we had a good many of the manholes, it worried me very much for fear that it would be repeated, and the company might have to pay a lot of damages, especially in districts like that around William and Nassau, where there are a good many people about. If an explosion took place in the daytime, it might lift a few of them up. However, I got around the difficulty by putting a little bottle of chloroform in each box corked up with a slight hole in the cork. The chloroform being volatile, and very heavy, settled in the box and displaced all the air. I have never heard of an explosion in a manhole where this chloroform had been used. Carbon tetrachloride, now made electrically at Niagara Falls, is very cheap and would be ideal for the purpose. Edison has never paid much attention to warfare, and has in general sustained to develop inventions for the destruction of life and property. Some years ago, however, he became the joint adventure of the Edison-Simms torpedo with Mr. W. Scott Sims, who sought his cooperation. This is a dirigible submarine torpedo operated by electricity. In the torpedo proper, which is suspended from a long float so as to be submerged a few feet underwater, are placed the small electrical motor for propulsion and steering and the explosive charge. The torpedo is controlled from the shore or ship through an electric cable, which it pays out as it goes along. And all operations of varying the speed, reversing, and steering are performed at the will of the distant operator by means of currents sent through the cable. During the Spanish-American War of 1898, Edison suggested to the Navy Department the adoption of a compound of calcium carbide and calcium phosphite, which when placed in a shell and fired from a gun, would explode as soon as it struck water and ignite, producing a blaze that would continue several minutes and make the ships of the enemy visible for four or five miles at sea. Moreover, the blaze could not be extinguished. Edison has always been deeply interested in conversation, and much of his work has been directed toward the economy of fuel and obtaining electrical energy directly from the consumption of coal. Indeed, it will be noted that the example of his handwriting shown in these volumes deals with the importance of obtaining available energy direct from the combustible without the enormous loss in the intervening stages that makes our best modern methods of steam, generation, and utilization so barbarously extravagant and wasteful. Several years ago, experimenting in this field, Edison devised and operated some ingenious pyromagnetic motors and generators, based, as the name implies, on the direct application of heat to the machines. The motor is founded upon the principle discovered by the famous Dr. William Gilbert, court physician to Queen Elizabeth and the father of modern electricity, that the magnetic properties of iron diminish with heat. At a light red heat, iron becomes non-magnetic, so that a strong magnet exerts no influence over it. Edison employed this peculiar property by constructing a small machine in which a pivoted bar is alternately heated and cooled. It is thus attracted toward an adjacent electromagnet when cold and is uninfluenced when hot, and as the result, motion is produced. The pyromagnetic generator is based on the same phenomenon, its aim being, of course, to generate electrical energy directly from the heat of the combustible. The armature, or moving part of the machine, consists in reality of eight separate armatures all constructed of corrugated sheet iron covered with asbestos and wound with wire. These armatures are held in place by two circular iron plates through the center of which runs a shaft, carrying at its lower extremity a semicircular shield of fire clay which covers the ends of four of the armatures. The heat of whatever origin is applied from below and the shaft being revolved, four of the armatures lose their magnetism constantly, while the other four gain it, so to speak. As the moving part revolves, therefore, currents of electricity are sent up in the wires of the armatures and are collected by a commutator, as in an ordinary dynamo, placed on the upper end of the central shaft. A great variety of electrical instruments are included in Edison's inventions, many of these in fundamental or earlier forms being devised for his systems of light and power, as noted already. There are numerous others and it might be said with truth that Edison is hardly ever without some new device of this kind in hand, as he is by no means satisfied with the present status of electrical measurements. He holds in general that the meters of today, whether for heavy or for feeble currents, are too expensive and that cheaper instruments are a necessity of the times. These remarks apply more particularly to what may be termed in general circuit meters. In other classes Edison has devised an excellent form of magnetic bridge, being an ingenious application of the principles of the familiar Wheatstone bridge used so extensively for measuring the electrical resistance of wires. The testing of iron for magnetic qualities being determined by it in the same way. Another special instrument is a dead beat galvanometer, which differs from the ordinary form of galvanometer in having no coils or magnetic needle. It depends for its action upon the heating effect of the current, which causes a fine platinum iridium wire enclosed in a glass tube to expand, thus allowing a coiled spring to act on a pivoted shaft carrying a tiny mirror. The mirror as it moves throws a beam of light upon a scale and the indications are read by the spot of the light. Most novel of all the apparatus of this measuring kind is the odoroscope, which is like the tassimeter described in an earlier chapter, except that a strip of gelatin takes the place of hard rubber as the sensitive member. Besides being affected by heat this device is exceedingly sensitive to moisture. A few drops of water or perfume thrown on the floor of a room are sufficient to give a very decided indication on the galvanometer in circuit with the instrument. Barometers, hygrometers, and similar instruments of great delicy can be constructed on the principle of the odoroscope, and it may also be used in determining the character or pressure of gases and vapors in which it has been placed. In the list of Edison's patents at the end of this work may be noted many other of his miscellaneous inventions covering items such as preserving fruit in vacuo, making plate glass, drawing wire, and metallurgical processes for treatment of nickel, gold, and copper ores, but to mention these inventions separately would trespass too much on our limited space here. Hence we shall leave their interested reader to examine that list for himself. From first to last Edison has filed in the United States patent office in addition to more than fourteen hundred applications for patents, some one hundred twenty caveats and embracing not less than fifteen hundred inventions. A caveat is essentially a notice filed by an inventor, entitling him to receive warning from the office of any application for a patent for an invention that would interfere with his own during the year while he is supposed to be perfecting his device. The old caveat system has now been abolished, but it served to elicit from Edison a most astounding record of ideas and possible inventions upon which he was working, and many of which he of course reduced to practice. As an example of Edison's fertility and the endless variety of subjects engaging his thoughts, the following list of matters covered by one caveat is given. It is needless to say that all the caveats are not quite so full of plums, but this is certainly a wonder. Forty-one distinct inventions relating to the phonograph, covering various forms of recorders, arrangement of parts, making of records, shaving tool, adjustments, etc. Eight forms of electric lamps using infusible earthy oxides and brought to a high incandescence in vacuo by high potential current of several thousand volts. Same character as impingement of x-rays on object in bulb. A loud speaking telephone with quartz cylinder and beam of ultraviolet light. Four forms of arc light with special carbons. A thermostatic motor. A device for sealing together the inside part and bulb of an incandescent lamp mechanically. Regulators for dynamos and motors. Three devices for utilizing vibrations beyond the ultraviolet. A great variety of methods for coating incandescent lamp filaments with silicon, titanium, chromium, osmium, boron, etc. Several methods of making porous filaments. Several methods of making squirted filaments of a variety of materials of which about 30 are specified. 17 different methods and devices for separating magnetic ores. A continuously operative primary battery. A musical instrument operating one of Hemholz's artificial larynxes. A siren worked by explosion of small quantities of oxygen and hydrogen mixed. Three other sirens made to give vocal sounds or articulate speech. A device for projecting sound waves to a distance without spreading and in a straight line on the principle of smoke rings. A device for continuously indicating on a galvanometer the depths of the ocean. A method of preventing in a great measure friction of water against the hull of a ship and incidentally preventing fouling by barnacles. A telephone receiver whereby the vibrations of the diaphragm are considerably amplified. Two methods of space telegraphy at sea. An improved and extended string telephone. Devices and method of talking through water for considerable distances. An audio phone for deaf people. Sound bridge for measuring resistance of tubes and other materials for conveying sound. A method of testing a magnet to ascertain the existence of flaws in the iron or steel composing the same. Method of distilling liquids by incandescent conductor immersed in the liquid. Method of obtaining electricity directly from coal. An engine operated by steam produced by the hydration and dehydration of metallic salts. Device and method for telegraphing photographically. Carbon crucible kept brilliantly incandescent by current in vacuo for obtaining reaction with refractory metals. Device for examining combinations of odors and their changes by rotation at different speeds. From one of the preceding items it will be noted that even in the 80s Edison perceived much advantage to be gained in the line of economy by the use of lamp filaments employing refractory metals in their construction. From another caveat filed in 1889 we extract the following which shows that he realized the value of tungsten also for this purpose. Filaments of carbon placed in a combustion tube with little chloride chloride tungsten or titanium passed through hot tube depositing a film of metal on the carbon or filaments of zirconia oxide or alumina or magnesia thoria or other infusible oxides mixed or separate and obtained by moistening and squirting through a dye are thus coated with above metals and used for incandescent lamps. Osmium for a volatile compound of steam thus deposited makes a filament as good as carbon when in vacuo. In 1888 long before there arose the actual necessity of duplicating phonograph records so as to produce the replicas in great numbers Edison described in one of his caveats a method in process much similar to the one which was put into practice by him in later years. In the same caveat he describes an invention whereby the power to indent on a phonograph cylinder instead of coming directly from the voice is caused by power derived from the rotation or movement of the phonogram surface itself. He did not however follow up this invention and put it into practice. Some 20 years later it was independently invented and patented by another inventor. A further instance of this kind is a method of telegraphy at sea by means of a diaphragm in a closed porthole flushed with the side of the vessel and actuated by a steam whistle which is controlled by a lever similar to a Morse key. Our receiving diaphragm is placed in another and nearby chamber which is provided with very sensitive stethoscopic ear pieces by which the Morse character sent from another vessel may be received. This was also invented later by another inventor and is in use today but will naturally be rivaled by wireless telegraphy. Still another instance is seen in one of Edison's caveats where he describes a method of distilling liquids by means of internally applied heat through electric conductors. Although Edison did not follow up the idea and take out a patent this system of distillation was later hit upon by others and is in use at the present time. In the foregoing pages of this chapter the authors have endeavored to present very briefly a sketching notion of the astounding range of Edison's practical ideas but they feel a sense of impotence in being unable to deal adequately with the subject in the space that can be devoted to it. To those who, like the authors, have had the privilege of examining the voluminous records which show the flights of his imagination there comes a feeling of utter inadequacy to convey to others the full extent of the story they reveal. The few specific instances above related, although not representing a tithe of Edison's work, will probably be sufficient to enable the reader to appreciate to some extent his great wealth of ideas and fertility of imagination and also to realize that this imagination is not only intensely practical but that it works prophetically along lines of natural progress.