MR EDISON'S INVENTIONS.

Globe, Volume XX, Issue 1574, 6 March 1879, Page 4

MR EDISON'S INVENTIONS.

[London "Times," January 2nd.]

Professor Barrett lectured on Monday at the London Institution on "the Phonograph, the Tarimeter, and the Carbon Telephone." After a brief reference to his lecture of last Christmas, when he announced that an invention had been made of an instrument by which the voice would be recorded and reproduced by simple machinery, he proceeded to give a brief biography of the inventor, Mr Edison. Born in 1847 of humble parents, the schooling he had was poor and fragmentary ; but, as in the case of the illustrious Faraday, his real education began when his boyhood ended. At twelve years of age be had to earn his bread by selling newspapers in the cars of trains. In the corner of a luggage van he arranged a •mall ohemical laboratory, where he made experiments during the transit of the car from town to town. He obtained a printing press, and started a diminutive weekly newspaper, the " Q-rand Trunk Herald," printed in the train itself. Next, before he was twenty, he entered a telegraph office, and not only made himself an expert telegraphist, but was able to repair and improve the instruments in daily use. He afterwards was employed by the Western Union Company as their " profes•ional inventor." Though not yet thirty-two years of age, he is said to have taken out 300 patents, but it must be remembered that by the American patent laws one invention alono has been known to have been secured by no fewer than forty-six patents. The public might suppose that Edison invented with facility; but the fact is that all his inventions are the offspring of incessant work, profound technical knowledge, and ready resource. One of the earliest and simplestof Edison's inventions was the so-called "electricpen." Here there is no new scientific principle, but an ingenious application of known principles, whereby a very swift to and fro motion is given to a needle point by a very tiny electromagnet. The point hardly projects the hundredth of an inch. This finely punctures the paper written on, which thus becomes a stencil-plate, from which any number of copies up to 2000 or more can be printed. A single voltaic cell i» sufficient to supply the

force which gives motion to tho small electromagnet of the pen, driving the small wheel and crank that work the needle. Mere ingenuity in contriving machines doea not add to the sam of human knowledge, and if Mr Ediaon were nothing more than a clever inventor ws should feel less interest in him. It is however, a noticoablo feature in Edison's inventions that in general they contain a new principle, some original observation in incentive science, which entitle* him to the rank of a discovereras well as of'an inventor. Such is the character of the elecro-motagraph. It was an entirely new method of receiving telegraphic messages, and was discovered by Edison in 1872. Ho found that messuges could bo roccived by the well known Morse recorder without the use of any magnet. In f;*ct, all that is needed in this pimple telegraphic instrument is a band of moistened paper drawn beneath a metal style. He hod noticed that when an electric current passed from the paper to the point resting on it the friction of the moving paper was lessoned. Hence, if the paper were drawn forward with a uniform force, it would slip more easily beneath the point the moment the current passed. He arranged that this slipping motion should be converted into audible signals by means of a local battery and a sounder. The advantage of the instrument was its extreme sensitiveness, it having been worked over a circuit of 200 miles with only two cells, so that with weak currents unable to affeet ordinary instruments the electro-motograph can receive messagrs. It is said, too, to have been worked at the rate of 1200 words per minute. The promptness of motion led Edison to use it also as a telephonic receiver. The slipping of the point gives rise to a feeble sound, which is repeated as often as the current passes, so that if 264 slips occur in a second, the note 0 will be heard. The cause of the alteration of the friotion between the point and the paper has not been explained ; but it occurs only at the negative pole, and hi nee it may be due to that peculiar repulsive effect to which Mr Crookes has quite recently drawn attention. In this discovery we have a characteristic glimpse of Edison. If Faraday had noticed the slipping, he would have worked to find its cause. Edison seizes the fact and applies it to purposes of practical utility, leaving the ex planation and generalization to other minds. Both types of men are necessary ; tho intellectual progress of tho ago is due to the one, the material progress to the other. The passion for invention is as genuine as the passion for discovery, and wo ought not to disparage the inventor because lie seeks to gain benefit from his toil by obtaining a patent for his invention. Tho practice is sanctioned by such eminent patentees as Sir C. Wheatstone and S»r W. Thomson. _ Pro fessor Barrett then described the invention of quadruplex telegraphy in 1874. This he considered the most important piece of work from a practioai point of view which Edison has yet accomplished. Currents of electricity may bo made to vary in two different ways—namely, in strength and in direction. If one telegraphic instrument can be made to work with change of strength only, and another with change of direction only, it will bo pos sible to work the two together, if we can alter the strength of the currents without changing the direction, or change their direction without affecting their strength. The first can be effected by changing the pole, the second by putting more battery power into the circuit. Each instrument for doing this may beso arranged that it is affected only by incoming and not by outgoing currents ; hence two messages may pass from each end along one wire with each pair of instruments, so that four messages may pass simultaneously. The plan is largely in use in America, and in England between London and Leeds. In America such duplex messages travel 1100 miles and are automatically printed at the rate of 58 words a minute. The exac f " balancing " of the currents was Edison's great difficulty, and Professor Burreit described with photographs shown on a screen the appliances he had successively invented. The carbon rheostat involves an important prinoiple which Edison may justly claim to have made his own. The principle involved is the effect of pressure on the electric conductivity of solids. Hence, by squeezing powdered carbon (and plumbago is but car bon) a considerable variation in the conducting power is produced. It has been said that M. Clerao discovered this ten years but Professor Barrett has found no trace of this. The first use to which Edison put this curious property was the construction of an instrument called a " carbon" or "pressure relay." This was the father of a numerous family—the carbon telephone, the microphone, and the carbon rheostat. In the telephone, now so well known, the voice has to do the work of creating the current, as well as making it vary. In the carbon telephone, buttery power gives the current, and the voice ouly varies the resistance and so causes variations in the current which are at the other end produced. Drawings were shown of the different successive attempts to effect the changes in resistance. By this apparatus the voice can be transmitted more loudly than it is spoken by adding battery power. It is not necess»ry to speak into the mouthpiece; to do so a few feet ofE has the same effect. The receiving instrument has a disc of stout iron, not of thin, as in the Bell telephone ; and some experiments were shown wi'.h this improvement. The tasimeter waß but briefly referred to, as it had got out of order during the lecture. In conclusion, " Rule Britan nia " was played on a cornet-apiston close to the receiver of a phonograph, and was reproduced, though shorn of all brilliancy, in a manner telling enough to arouße the audience to demand an encore.

A reporter of the "New York Sun " hud an interview on the 18th December with Mr Edison. Mr Edison stated that several patents for the electric light had been granted him at Washington ; but, as the particulars were kept secret until the patent was taken out, and as he did not intend to take them out inside of six months, the limit allowed him by the Patent Office, he should postpone his final experiments i'or lighting Mania Park until he found the machine that would give the greatest amount of electricity per horsepower. Meanwhile, he was making many little generators of different forms tor the purpose of arriving at this knowledge. He estimated that the total number of generators he would use in his final experiments in lighting the park would cost him from £6OOO to £BOOO. He proposed in the case of the little experimental generators he was making to run them with weights. Estimating all the expenses, with the poorest e gines and the poorest economy, where, in fact, the expenses were very high, if he could get six lights per horse-power (and he was confident on this head), each light would cost, in his belief, only one third the amount the production of the same amount of light by gas coat. Mr Edison continued—" With one-horse power the Jablochkoff candle gives a light equal to 66 gas j-*ts; with the same power I get only six lights, each equal to one gas jet. People look at each other and ask, How can I hope to compete with the candle ? Tne answer is easy. The Jablochkoff candle consumes carb >n Hi»t costs three times more than the power that supplies the electricity. Hence, at the emue expense, I could use 18 of my lights. The candle cannot be subdivided. Its light is so intense that a ground glass globe is used to modify its power. This involves a loss of 50 per cent, of light, reducing the value of the 66 gas jets to 33. Thus, at the same expense, we have 18 of my lamps of one gas jet each to one carbon candle equal to 33 gas jets. These 18 lights judiciously distributed over the area to be lighted double their value when compared to a single lamp of 18 gas jets. What I mean is this—Here is a room with one gas jet; the gas jet is equal to 15 candles, but 15 candleß distributed abound the room would give more light than the gas jet. On the same principle I say that one carbon candle equal to 33 gas jets would give only about one-half the light that 18 of my lamps would give. They would actually surpass the Jablochkoff candle in economy when used in lighting up a given area." The conversation next turned upon the carbon telephone. Mr Edison said he had sold the right to use the instrument in France for 500,000 f. He also stated he had sold out his right in the phonograph to the Edison Phonograph Company, who were now selling machines at from £2O to £25 each; they were also getting out a small machine that would be retailed at £l, it would talk as clearly as the more expensive machine, but would not receive so many

words at a time. Referring to the annual meeting of the American Electrical Society and Mr Bliss's assertion that he could talk through the Atlantic cable, Mr Edition shook bis head.aaying, " I think that impossible" Ho also declared that his roceiver tor throwing the sound out into a room could not bo attached to the Q-ray or Bell telephone*. The " New York World" of the same date Bayg ._" Mr Edison will not fix any time when ho will be able to say that he has completed hia work. Some months, at least, must elapse before a public exhibition of the light will be given, as the experiments cover a wide field in every branch of mechanics, electrical science, metallurgy, and correlation of force, and are probably the moat complete and costly ever undertaken."