24 MUSICAL SOUNDS PRODUCED BY HIDROGEN GAS. 



a current of hidrogen ; for an inflamed ftream of the vapours 

 of alcohol or ether, a lighted taper, &c, are incapable of pro- 

 ducing any found. 

 Circumftances. L e t us novv examine the circumftances of the experiment. 

 The place of There muft be a point which may be called the fonorous point ; 

 the fonorous a * wmcn the vibrations, communicating an undulatory motion 

 point. to the air, are produced. This point is the place of combuftion; 



for if this be made to alter its fituation, the founds will vary, as 

 M. Piclet has proved in a feries of experiments. He has like- 

 wife obferved, by means of fmokc with which he filled the 

 tube, a continual fucceffion of vibrations at this point ; thefe 

 vibrations produce the waves, which proceeding with a deter- 

 minate velocity, ftrike againft the fides of the tube, and are re- 

 flected with a velocity equal to that with which they arrived. 

 Undulations at When the diftance of the fides of the tube is fuch that the ar", 

 accord' witlTthe ternate reflections are equal to the vibrations natural to the fo- 

 refonaut echo of norous caufe, the found increafes in intenfity, and becomes mu- 

 fically appreciable. It appears likewife that the waves thus 

 reflected do re-act on the primitive vibrations produced at the 

 place of combuftion, fo as to render them harmonioufly regu- 

 The found does I ar# p or a certain fpace of time is almoft always neceffary be- 

 * fore the inftrument acquires a regular and full found ; and the 

 Its tone. tone or pitch of the tube will be more or lefs acute according 



to the greater or lefs number of undulations which take place in 

 a given time. 

 The temperature There is another fact effential to be obferved in this experi- 

 tube Vhotteft at ment - The temperature of the column of air is not the fame 

 the burning through all its length. At the fonorous point, that is to fay the 



more , remote° ler P Iace of combuftion > the temperature is very high ; fo much fo 

 that the end of the adjutage of the glafs through which the hi- 

 Alcohol or ether drogen paffes, is conftantly in a ftate of ignition. If an in- 

 free of heat!" flame ^ ftream of the vapours of alcohol or ether be fubftituted 

 inftead of the hidrogen, the heat is evidently lefs. From fome 

 experiments it alfo feems probable that the temperature of the 

 room, and the purity of its air, may affect the fuccefs of the 

 experiment. 

 Conjecture that My experiments have been directed to afcertain the caufe of 



the fauna is thefe phenomena, how and by what means thete fonorous vi- 

 produced by the , * ■■ . * 



rapid producTionbrations are produced. We know that water is formed du- 

 and collapfion of r j n g the combuftion of hidrogen : this water appears in the 

 aqueous vapour. ^^ f vapour. The temperature of the place of combuftion 



being 



