130 Prof. Hare's improved Eudiometrical Apparatus. 



hydrogen, and 50 times of atmospheric air. By the large sliding- 

 rod instrument, this object is effected at once by taking 42 

 measures of the one, and 100 measures of the other. 



IV. Barometer-Gauge Eudiometer. 

 The following is an engraving of the barometer-gauge eudio- 

 meter for explosive mixtures. R is a glass receiver. Within 

 the receiver near W is an arc of platina, by the ignition of 

 which the gas is inflamed. C is a cock with three orifices, 

 either of which may be made to communicate with the re- 

 ceiver, according to the position of the lever L. More than 

 one of the orifices cannot be open at once, but all may at the 

 same time be closed. The barometer-gauge GG is seen be- 

 side the receiver, with which it communicates through the 



pipe P, and the valve cock V, by means of which the commu- 

 nication between the gauge and receiver may be suspended 

 at pleasure. The pipe A conveys to the receiver the gaseous 

 mixture from the bell-glass B. By one of the pipes D, a com- 

 munication 



