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A. M. Mayer — Researches in Acoustics. 



tube, T. The sound from the bar is conveyed to the ear, at 

 E, by means of a tube (fig. 4). One branch of this bifurcated 

 tube leads through a rubber tube to the pipe, P, of the box, 

 fig. 3. The other branch leads to the fork, F, the number of 



LCX^E 



whose beats per second made with the vibrating bar is meas- 

 ured by a chronometer. The pipe, S, allows the steam to 

 issue when water is boiled in the box, C 7 , by a gas lamp. The 

 flow of gas through this lamp was neatly regulated by a stop- 

 cock turned by a long lever. The box, C, is covered, except 

 at the bottom, with thick felt. 



To determine the frequencies of vibration of a bar through 

 a range of temperature from 0° to 100°, the following method 

 was used : The box, C, was filled with ice, surrounding the 

 inner box, C. It thus remained for an hour so that the boxes 

 were cooled down to 0', and the moisture in the inner box has 

 been condensed so far as it can be at 0°. The bar, which has 

 been in ice for two hours, is wiped dry and quickly intro- 

 duced into the inner box. A thermometer, T (made by Baudin 

 and corrected), entered the boxes through stuffing boxes, 

 and whose bulb touched the under surface of the bar, was 

 read till it became stationary. The bar was now vibrated and 

 its frequency of vibration determined for the temperature 

 given by the thermometer. 



The lamp was now placed under the box and the water in it 

 boiled till the thermometer reached its maximum reading and 

 the reading remained stationary during a half-hour. The 

 vibration frequency at this temperature was taken. The flame 

 of the lamp was now lowered and the box allowed to cool very 

 slowly, at the rate of 1° fall of temperature in about eight min- 

 utes. When the thermometer read 80°, 60°, 40°, the flame of 

 the lamp was carefully, adjusted, so that these successive tern- 



