Oct. 3 I, 1878] 



NATURE 



699 



to successfully accomplish the grand object of repro- 

 ducing articulate speech at a distance" (p. T^. 



A little further on Mr. Prescott remarks :— 



" From the reading of the text [Prof. Bell's lecture in 

 London] it might be erroneously inferred that the apparatus 

 shown [a water variable-resistance telephone] was invented 

 by Prof. Bell, and exhibited by him at the Centennial Exhi- 

 bition. Prof. Bell neither invented nor exhibited it. The 

 figure [given by Bell] represents the transmitting portion 

 •of Elisha Gray's original speaking telephone, the first 

 articulating telephone ever invented. Mr. Gray experi- 

 mented with the telephone at the Centennial Exhibition 

 in America in 1876, and showed it, among others, to 

 Prof. Barker, but did not exhibit it to the judges." 



Even with reference to the present shape of Bell's tele- 

 phone, Mr. Prescott denies that Bell was its inventor and he 

 adduces evidence to show that the present portable form 

 of the handle telephone was due to Dr. Channing and 

 Mr. Jones, of Providence, R.I. This, however, is a minor 

 matter, but the question of priority of invention of the 

 principle of the articulating telephone is one of general 

 interest and importance. 



To the consideration of this matter the Count du 

 Moncel brings not only an independent and unbiassed 

 mind, but also a profound technical and historical know- 

 ledge of the various applications of electricity. And in 

 the following opinion, which he expresses, we entirely 

 agree : — 



"Si M. Bell a etd le premier a construire et h. rendre 

 pratique le t^ldphone parlant, M. Ehsha Gray avait le 

 j)remier congu le principe de cet instrument et I'avait 

 combind en electricien consommd." 



A similar opinion is expressed in a very able and lucid 

 discourse by a well-known electrician, Mr. F. L. Pope, 

 delivered last December before the American Electrical 

 Society at Chicago, reprinted in Prescott's book. At the 

 same time we must bear in mind Prof. Graham Bell had 

 for some time back also been at work at a similar problem 

 to that which had led Gray to the conception of an arti- 

 culating telephone, namely, the problem of multiple tele- 

 graphic transmission by means of harmonic vibrations, 

 and from this subject was led to the discovery of his 

 magneto-electric telephone. As Mr. Pope remarks, "when 

 we consider that each was working in ignorance of the 

 labours of the other, the singular coincidence in the 

 results they finally obtained is not a little remarkable." 

 To Gray and Bell a third name has also to be added, 

 namely, that of Edison, to whose work we shall refer 

 more fully in another article. These three names stand 

 •conspicuously forth in connection with the discovery of 

 the speaking telephone, and we therefore propose to 

 trace the relationship each bears to this subject. 



The dominant idea that stimulated each of these in- 

 ventors was the possibility of transmitting several mes- 

 sages simultaneously along one wire. By his patent of 

 1870 Varley had led the way to the method by which 

 this could be accomplished ; he succeeded, in fact, 

 in transmitting secondary currents, generated by the 

 vibration of a tuning fork, in the primary circuit of an 

 induction-coil, concurrently with the ordinary Morse 

 signals, the former not sensibly affecting the usual 

 •electro-magnetic receiving apparatus, but producing 

 audible signals on a peculiar receiver of his own. After 

 this, in September, 1874, La Cour, of Copenhagen, 

 patented an apparatus for multiple transmission, founded 

 on a modification of Varley' s plan. In this case the re- 

 ceiver was a tuning-fork, controlled by an electro-magnet, 

 and tuned in unison with the transmitting fork, hence it 

 was capable of being thrown into sympathetic vibration 

 by the electric waves started by the latter. A series of 

 such duplicate forks was employed corresponding to the 

 notes of the musical scale, and it was found that the 

 intermittent currents of several of these forks could be 

 simultaneously transmitted without confusion, each re- 



ceiver selecting and vibrating under its appropriate 

 system of electro-magnetic impulses. Early in 1875 

 Gray, of Chicago, patented a somewhat similar, but 

 more perfect arrangement. Gray' s caveat, or application 

 for his patent, dates from August, 1874, so that in point 

 of fact he anticipated La Cour's method. Instead of 

 using tuning-forks Gray employed strips of steel as being 

 lighter and more sensitive ; each transmitting reed 

 instrument had, of course, its fellow at the receiving 

 end, which promptly responded to its own system of 

 waves, acting upon it through an adjacent electro-magnet. 

 The idea of synchronising the movements of two in- 

 struments at wide intervals apart by employing the prin- 

 ciples of isochronous vibration is not novel, it was carried 

 out by Helmholtz in his experiments on vowel sounds ; 

 and still earher distant isochronous pendulums were used 

 in telegraphy to control machinery, by Vail, in 1837, 

 Ronalds in i86r, and Hughes in his printing-telegraph. 

 But Gray accomplished more than this. Reiss, in 1862, 

 had shown by his telephone how the rate of vibration 

 might be electrically transmitted and reproduced, but the 

 amplitude and mode of vibration were lost ; Gray, towards 

 the close of 1874, discovered a method whereby the proper 

 a7nplitude of each vibration or combination of vibrations 

 could be reproduced, "by causing the effective strength 

 of the electric current, by which the transmission is 



Fig. I. — Original arrangement for the electric transmission of speech 

 designed by Gray. A current from the battery on the right passes into 



^i a vessel containing water, into which dips a wire attached to the vibrating 

 membrane and in circuit with the line. (From Du Moncel's work.) 



effected, to rise and fall with the varying amplitude of 

 the sonorous waves which are to be reproduced." Hence, 

 as Mr. Pope, in the discourse to which we have alluded, 

 goes on to remark : — " This having been accomplished, 

 it was not difficult to foresee that two practical applica- 

 tions might be expected to follow, namely, multiple 

 transmission and vocal transmission." 



There yet remained however the difficulty of impres- 

 sing upon an electric current the ra-pidly-changing forms 

 of the sonorous waves which occur during the act 

 of speaking. In the beginning of 1876 Gray conceived 

 the idea of accomplishing this by attaching to a stretched 

 membrane, such as was used by Reiss, an arrange- 

 ment whereby the movements of the membrane should 

 produce proportional alterations in the resistance of an 

 otherwise constant electric circuit. Undulatory cur- 

 rents of fluctuating strength would thus be set up by 

 the voice, and these, acting electro-magnetically upon a 

 diaphragm at the far end — to which was attached a piece 

 of soft iron— would cause it to be thrown into vibrations 

 corresponding to those existing at the transmitting end. 

 The problem of the transmission of speech was thu 



