THE PYROPHONE. 45] 



(1 



" If two flames of a certain size be introduced into a tube made of glass, and 

 if they be so disposed that tJiey reach tlie tliird part of the tube's height (meas- 

 ured from the base), the flames will vibrate in unison. This phenomenon con- 

 tinues as long as the flames remain apart ; but as soon as they are united the 

 sound ceases." 



Passing on to his exi^eriments, M. Kastner thus gives his account : 



" I took a glass tube, the thickness of which was 2^ millimetres ; this tube 

 was 55 centimetres long, and its exterior diameter measured 41 millimetres. Two 

 separate flames of hydrogen gas were placed at a distance of 183 millimetres from 

 the base of the tube. These flames, while separated, gave F natural. 



"As soon as the flames are brought together, which is done by means of a 

 very siuiple mechanism, the sound stops altogether. If, letting the flames re- 

 main apart, their position is altered until they reach one-third of the total length 

 of the tube, the sound will diminish gradually ; and it wih cease completely if 

 the flames go beyond one-half the length of the tube ; under this (one-half the 

 length of the tube) the sound will increase until the flames are brought to one- 

 fourth of the tube's total length. This latter point being reached, the sound will 

 not cease immediately, even if the two flames are placed in contact one with the 

 other; but the two flames, thus united, continue vibrating in the same manner 

 as a single flame would. 



" The interference of the singing-flames can only be obtained under certain 

 conditions. It is important that the length of the tubes should be varied accord- 

 ing to the number of the flames, the height of which has only a limited action or 

 influence over the phenomenon ; but the special shape of the burners is a matter 

 of considerable importance. 



" These experiments, which I undertook two years ago, induced me to con- 

 struct a musical instrument, possessing quite a novel sound, which resembles the 

 sound of the human voice. This instrument, M'hich I term the Pyrophone, is 

 formed by three sets of keys {claviers) disposed in a similar manner to that em- 

 ployed for the conjunction of the organ-key tables; a very simple mechanism 

 causes every key of the diflferent sets to communicate with the supply-pipes in 

 the glass tubes. As soon as a key is pressed upon, the flames, by separating, 

 create a sound ; but when the keys are left untouched, the flames are brought 

 together and the sound stops." 



In consequence of this communication a commission from the Aca- 

 demic des Sciences de Paris was selected for the examination of this 

 curious invention, consisting of Messrs. Jamin,Regnault, and Bertrand, 

 three distinguished members of that Academy, who sliowed a lively- 

 interest from a scientific point of view in M. Kastner's discovery. 

 After fresh experiments, M. Kastner has succeeded in substituting the 

 ordinary illuminating gas for hydrogen. gas in working this pyrophone, 

 and his friend the Baron Larrey was again the interpreter to 1' Acade- 

 mic des Sciences of this new discovery, which much facilitates the em- 

 ployment of the luminous musical instrument. M. Kastner thus ex- 

 presses himself in his new report presented to the Institut de France, 

 December 7, 1874 : 



" The principal objection which has been made to the working of the pyro- 

 phone is the employment of hydrogen gas. From a practical point of view, this 



