Sept. 6, 1877] 



NATURE 



403 



descent gases tliat have emanated in enormous quantities 

 from the interior, will remain for some time. 



The observations of the spectrum show beyond doubt 

 that the decrease in the light of the star is in connection 

 with the cooling of its surface. The violet and blue parts 

 decreased more rapidly in intensity than the other parts, 

 and the absorption bands, which crossed the spectrum, 

 have gradually become darker and broader. 



Finally Herr Vogel regrets that the news of the dis 

 covery of the new star by Herr Schmidt was only known 

 so late, as doubtless during the first few days most 

 interesting changes must have occurred in the spectrum, 

 while the star rapidly decreased in brightness. Herr 

 Vogel recommends that in case of appearance of other 

 new stars no time should be lost before spectral observa- 

 tions are made, and points out that even with small 

 telescopes very useful results may be obtained, if care is 

 taken that spectroscopes are used of sufficiently low 

 power of dispersion. 



The position of the new star with regard to two neigh- 

 bouring stars of magnitudes 91 and 94 Herr Vogel has 

 determined as follows : — 



Nova — if- gm'l (Bonn. Durchmtist., + 42°, 4184) 

 1877-0 Aa =- 25s'oo AS= + i'i5"'4 

 Nova - * 9in'4 {Bonn. Durckmust., -F 42°, 41S5) 

 18770 Aa = - 355-34 A5 = - l' I3"-2. 



As the first of the comparison stars has been determined 

 at the meridian circle of Bonn, the position of the new 

 star is : — 



1877-0, 2ih. 36m. 523-48 -H 42" 16' S4"-5. 



THE TELEPHONE ' 



TN the following paper I call instruments employed in the 

 transmission of musical sounds, tone telephones, and those 

 employed in the transmission of the human voice, articulating 

 telephones. 



In the year 1837, Page, an American physicist, discovered that 

 the rapid magnetisation and demagnetisation of iron bars pro- 

 duced what he called "galvanic music." Musical notes depend 

 upon the number of vibrations imparted to the air per second. 

 If these exceed sixteen we obtain distinct notes. Hence, if the 

 currents passing through an electro-magnet be made and broken 

 more than sixteen times per second, we obtain "galvanic music " 

 by the vibrations which the iron bar imparts to the air. The iron 



Fr.g.1 



^ 



a 



bjr itself mparts these vibrations by its change of form each 

 time it is magnetised or demagnetised. 



De la Rive, of Geneva, in 1843, increased these musical effects 

 by operating on long stretched wires which passed through open 

 bobbins of insulated wire. 



Philip Reiss, of Friedrichsdorf, in 1861, produced the first 

 telephone which reproduced musical sounds at a distance. He 

 utilised the discovery of Page by causing a vibrating diaphragm 

 to rapidly make and break a galvanic circuit. The principle of 

 his apparatus is shown Fig. I. 



h is a IioUow wooden box into which the operator sings through 

 the mouthpiece a. The sound of his voice throws the dia- 

 phr.\gm c into rapid vibration so as to make and break contact at 

 the pl.atinum points d ii each vibration. This interrupts the 

 current flowing from the batteries e as often as the diaphr.-igm 



I Paper read by Mr. W. H. Preece, Memb. Inst. C.E., at the Plymouth 

 Meeting of the British Association. For the sectional cuts we are indebted 

 to En^neering, 



vibrates, and therefore magnetises and demagnetises the electro- 

 magnet as often. Hence whatever note be sounded into the box 

 a the diaphragm c will vibrate to that note, and the electro- 

 magnet /"will similarly respond and therefore repeat that note. 



Musical sounds vary in tone, in intensity, and in quality. The 

 tone depends on the number of vibrations per second only ; the 

 inttnsity on the amplitude or extent of those vibrations; the 



quality on the form of the waves made by the vibratmg particles 

 of air. 



It is evident that in Reiss's telephone everything at the receiv- 

 ing end remains the same, excepting the number of vibrations, 

 and therefore the sounds emitted by it varied only in tone and 

 were therefore notes and nothing more. The instrument 

 remained a pretty philosophical toy and was of no practical 

 value. 



Cromwell Varley, in 1870, showed how sounds could be 

 produced by rapidly charging and discharging a condenser. 



After alluding to the invention of Mr. Elisha Gray (Nature, 

 vol xiv. p. 30), Mr. Preece said : — 



It remained for Prof. Graham Bell, of Boston, who has been 

 working at this question with the true spirit of a philosopher 

 since 1S72, to make the discovery by which tone, intensity, and 

 quality of sounds can all be sent, fie has rendered it possible 

 to reproduce the human voice with all its modulations at distant 

 points. I have spoken with a person at various distances up to 

 thirty-two mdes ; and through about a quarter of a mde I have 

 heard Prof. Bell breathe, laugh, sneeze, cough, and in fact 

 mike any sound the human voice can produce. Without 

 explaining the various stages through which his apparatus has 

 passed, it will be sufticient to explain it in its present form. 

 Like Reiss he throws a diaphragm into vibration, but Prof. 

 Bell's diaphragm is a disc of thin iron a, which vibrates in 

 front of a soft iron core b, attached to the pole of a permanent 

 bar magnet N S (Fig. 2). This core becomes magnetised by the 

 influence of the bar magnet N S, inducing all around it a 

 magnetic field, and attracting the iron diaphragm towards it. 

 Around this core is wound a small coil c of No. 3S silk-covered 

 copper wire. One end of this wire is attached to the line wire, 

 tlie other is connected to the earth. The apparatus at each end 

 is identically similar, so that it becomes alternately transmitter 

 and receiver, first being put to the mouth to receive sounds, and 

 then to the ear to impart them. Now the operation of this 

 apparatus depends upon the simple fact that any motion of the 

 diaphragm <; a'ters the condition of the magnet field surrounding 

 the core /', and any alteration of the magnet field, that is either 

 its strengthening or weakening, means the induction of a current 

 of electricity in the coil c. Moreover, tire strength of this 

 induced current depends upon the amplitude of the vibration. 



and its form or the rate of vibration. The number of cur ents 

 sent of course depends upon the number of vi brations of the 

 diaphragm. Now each current induced in the coil c passes 

 through the line wire to the coil t', and then it alters the 

 magnetisation of the core b^, increasing or diminishing its attrac- 

 tion for the iron diaphr.agm a^. Hence the diaphragm a} is 

 vibrated also, and every vibration of the diaphragm a must be 



