£70 ON THE SONOROUS PROPERTIES OF GASSES. 



have been made on their sonorous properties. We have 

 lately been occupied in makino^ a few experiments on this 

 subject, the results of which I send, in as concise a manner 

 as possible, for insertion in your celebrated Journal, if you 

 should think them of sufficient value. In some particulars 

 they are very incomplete. We were prevented from deter- 

 mining the intensity of the sound by surroundfng noises, 

 and variable winds ; but we purpose repeating and ex- 

 tending these experiments, at a more favourable opportu- 

 nity. 

 Apparatus Our apparatus consists of a small pair of double bellows, 



^ ■' ' fixed vertically in a wooden frame, having a brass screw 

 underneath it, to fit into the plate of an excellent, single 

 barrelled airpump. A thermometer is fixed against one 

 arm of the wooden frame, and a small flute pipe of an 

 organ (open at the end) against the other. A groove is 

 made through this arm to convey the wind from the bellows 

 to the pipe. See the dotted fine PI. VII, fig. 1. The whole 

 is covered by a glass receiver, 13 inches high, and 7 in dia- 

 meter ; and the bellows are put in motion by turning 

 ' backwards and forwards a bent wire, that passes through a 

 collar of leathers at the top of the receiver, and is attached 

 to another wire projecting from one end of a lever which 

 has its other extremity fastened to the feeder of the bellows. 

 Fig. 2. represents the pasteboard lining of the folds of the 

 bellows. 

 Modeof mak- After 80 strokes of the piston, the pipe was inaudible : 

 jiig the experi- after 200 strokes, the gas was transferred into the receiver 

 menu. from a bladder in the usual way; and the bridge of the 



mouochord was moved till the sound of the wire •..'as per- 

 ceived to be the octave below that of the pipe : then half 

 the length of the vibrating part of the wire, in thousandths 

 of the whole length, was set down in the fifth column of 

 the following table. In the experiments c, t/, n, p, r, 

 (column 1) the gas was transferred in four nearly equal por- 

 tions. The mouochord was previously tuned by a c toning 

 fork, to Earl Stanhope's " first bass c"*, Professor Chladni's 



* " Principles o.''ihe Scien.e of Tuning," i806» 



tttf 1 



