216 



suitable capillary tube witb rubber connections. A mercury buret, arranged 

 to receive the gas, was connected to the other end of the quartz tube in a 

 similar manner. Pinch cocks, one on the buret and one on the pipet, con- 

 trolled the connections witb the (luartz tube. The buret was jtrovided witb 

 a water jacket which was connected at its lower end with a level bottle so 

 arranged that the water could be drawn out and then itassed back into the 

 water jacket. This circulation and thorough mixing of the water were 

 necessary to prevent uneipial temperatures between the top and bottom of 

 the buret. Tlie water jacket was improvised from the outside of a Liebig 

 condenser. A thermometer, which showed tlu- t<'nii)erature of the water 

 and gas, was suspended about midway of the buret inside of the water 

 jacket. The quartz tube was heated by a bnnsen burner provided with a 

 wing tip which produced a broad flame. An asbestos board was suspended 

 about 5 mm. above the quartz tube, to lessen the radiation of heat. The 

 manipulation was: The temperature of the gas in the pipet, that is the 

 temperature at wliicli it was measured, was carefully read. The pinch- 

 cock connecting the buret to the quartz tube was opened and the burner 

 was lighted for three minutes. The increase in volume of the air in the 

 (|uartz tube produced by the heat, was cared f<.r in the buret. The pinch- 

 cock connecting the pipet to the quartz tube was opened and the level bottU? 

 was raised so that the gas and oxygen passed slowly and regularly over the 

 glowing platinum, generally about three nnnutes l>eing required. In no 

 case was there any indication of an explosion in the piju't even when the 

 velocity of the gas was greatly increased. The level tulie on the buret was 

 raised and the level bottle on the pipet was lowered so that the gas was 

 forced back from the buret into the pipet. The gas was then again passed 

 through the quartz tube over the glowing platinum into tbe buret. The 

 flame and the asl>estos board were removed and water was imured upnn tlie 

 ipiartz tube to cool it. After the quartz tube had reaclu'd i-dom tempera- 

 ture, tlie pinchcock (■onne( ting (he buret and quartz tube was closed. The 

 mercury in the l)uret and level tube was leveled. The water in the water 

 jacket was passed back :ind forth by means of the level Imttle until the 

 thermometer in the water jacket showed constant temi)erature. The mer- 

 cury in tbe buret and level tube was again carefully leveled and the volume 

 of gas was read. The final gas vnhune was always corrected for variation 

 from the initial tenii)erature. 



The process as described .above was tried with jiure hydrogen gas. 

 which was lu-ejiared by tlie ac(i(in of lioilcd dilute sulphuric acid upon 



