472 



NATURE 



\March 20, 1879 



paper is converted into a to-and-fro motion of a lever to 

 which the point is attached, and which is made to actuate 

 a bell, or " sounder," and give rise to audible signals in the 

 usual way. It is necessary to moisten the paper with a 

 solution of certain chemicals. Potash was at first used, 

 but a solution of sulphate of soda or of common salt and 

 pyrogallic acid is found to be best.^ 



"The advantage of this instrument, which Mr. Edison 

 calls an electro-motograph, is said to be its extreme sensi- 

 tiveness, it having been worked over a circuit of two 

 hundred miles with only two cells, so that with weak 

 currents, unable to affect ordinary instruments, the 

 electro-motograph can receive messages. More than 

 this, the speed of its working is greater than with the 

 ordinary instruments. Using it as a relay, that is, an 

 instrument for translating weak currents into strong ones, 

 no less than 1,200 words per minute have been transmitted 

 by its means, or five times as fast as it is possible for any 

 person to read the message which comes through the 

 instrument. So prompt and delicate is the motion of this 

 machine that Edison has applied it to the purposes of the 

 receiving instrument for the Reiss telephone, a musical 

 telephone that was made many years ago. The slipping 

 of the paper causes a slight sound. If, then, we sing a 

 certain note into the Reiss transmitting instrument, which 

 vibrates in unison with that note, we obtain the same 

 number of electric currents produced per second as we 

 had of sonorous vibrations in the moving diaphragm. 

 Thus, if we sounded the middle C we should get 264 

 vibrations, and there would be 264 electric currents, and 

 264 slips of the paper, thus producing a note of the same 

 pitch in a distant room. The cause of the curious slipping 

 has not been fully ascertained. It may possibly be due 

 to that peculiar repulsive effect to which Mr. Crookes has 

 lately drawn attention, and which produces the dark 

 region around the negative electrode during the continu- 

 ance of an electric discharge in a vacuum tube, or it may 

 simply be due to electrolytic action." 



It is, then, this principle which Edison has made use of 

 in his new receiver, which is of the simplest construction. 

 A diaphragm, preferably of mica, some four inches in 

 diameter, held in a suitable framework, has attached to 

 its centre a spring, or "pawl," the free end of which 

 rests on a little cylinder of chalk, capable of rotation by 

 the hand or other means. The chalk cylinder replaces 

 the paper in the electro-motograph. and is necessarily 

 impregnated with sulphate of soda, or other suitable 

 solution. As the cylinder is rotated, the friction of the 

 spring on the chalk causes the diaphragm to be pulled in 

 or pushed outwards, according to the direction of the 

 rotation. So far the operation is purely mechanical ; as 

 soon, however, as the current passes, either owing to 

 electrolytic action or the friction, it is lessened, and the 

 diaphragm tends to spring back to its normal position ; on 

 the cessation of the current the friction is restored, to be 

 lessened on the recurrence of another electric wave. 

 Thus, a series of tremors are given to the diaphragm 

 corresponding to the swiftly changing character of the 

 electric waves, and these again faithfully express the 

 motion of the diaphragm at the transmitting end. It 

 will thus be evident that the incoming current has simply to 

 do the work of liberating the already strained diaphragm. 

 As everyone knows, in Bell's telephone the voice has to 

 do the work of creating the current at the transmitting 

 end, and the feeble magneto-electric currents thus gene- 

 rated throw into motion the diaphragm at the receiving 

 end. In Edison's telephone this is not so. The 

 voice at the transmitting end has simply to vary the 

 electric resistance in the path of a current generated by 

 an ordinary voltaic battery ; stronger currents can thus 

 be sent along the line, and these arriving at the receiving 

 end, have merely to vary a mechafiical resistance, and 



' Practical difficulties have, we believe, been found in the working of the 

 motograph, so that it has not come into telegraphic use. 



not to do the work of overcoming the inertia of the 

 diaphragm. It is probable the rotating chalk cylinder 

 acts on the diaphragm with its attached spring like a 

 resined bow on a violin string; vibrations are set up, the 

 extent, rate, and manner of which are modified by the 

 varying friction due to the telephonic currents. Whether 

 these new receivers will retain their present efficacy 

 when in constant use remains to be seen. We should be 

 inchned to think the soft surface of the chalk will even- 

 tually wear with the friction, and that a more permanent 

 arrangement will have to be devised. No invention, 

 however, reaches perfection at once, and the present 

 receivers, excellent as is their performance, were, we 

 understand, hastily made in a few days, in comphance 

 with the urgent request of Mr. Edison's courteous repre- 

 sentative in London, Col. Gouraud. 



The instrument has the appearance of a small box 

 attached to the wall, and from which there projects a 

 single funnel. Sounds of singing, speaking, whistling, 

 sent from the other end, quite a mile off, were heard in 

 every part of a moderately sized room. Telephonic 

 connections, now so common in America, have been 

 established by Col. Gouraud between various business 

 houses in the city ; and we believe that shortly this 

 method of communication must become quite common. 



NOTES 



Dr. Miclucho'Maclay, the eminent Russian Naturalist and 

 New Guinea explorer, has been trying to rouse the Linnean 

 Society of New South Wales and the scientific public of Sydney 

 to the necessity of founding a zoological station, similar to that 

 at Naples. He tells of the great inconvenience he himself has 

 suffered during his residence at Sydney from the want of such a 

 station, even though the Hon. Mr. Macleay placed his museum 

 at his disposal. But Dr. Maclay's scheme embraces much more 

 than a station at Sydney, He has written to the German Eastern 

 Asiatic Society at Japan and to Mr. August Godeffroy at Samoa, 

 urging that similar stations be founded at these places, and he has 

 reason to believe that his proposals will not be without result at both 

 places. Thus should zoological stations be instituted at Sydney, 

 in New Zealand (as Dr. Maclay also proposes), in Japan, and at 

 Samoa, we might hope in a very few years to have a fairly com. 

 plete knowledge of the fauna of the Pacific. Dr. Maclay's pro- 

 posal deserves the heartiest encouragement, and we trust that 

 ere long it will be fully carried out. We hope the people of 

 Sydney, at any rate, will take Dr. Maclay's appeal to heart ; he 

 tells them, moreover, that he will judge of the intensity of the 

 scientific life of Australia by the interval which elapses between 

 the reading of his paper on the subject and the actual foundation 

 of the station. He shows what valuable results have followed 

 the foundation of the Naples station, and gives a few hints as to 

 how such a station at Sydney should be organised. We shall 

 be curious to see what will be the result of Dr. Maclay's fervent 

 appeal. 



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 The telegram containing the inquiry must not exceed twenty 

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 give any information which is not substantially included in the 

 latest notice posted at its own doors, nor does it give forecasts 

 of the weather on the Atlantic coasts of the British Isles; 

 although it is ready to furnish any information it possesses as to 

 the actual state of the weather on those coasts. The Meteoro- 

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