Biological Chemistry. 



barometer tube, but widened at the top and provided with 

 a side tube d, and a stopper /, is immersed in an outer 

 jacket b, to which at the bottom a bulb c is blown. Into 



this is introduced a liquid which 

 boils at a higher temperature 

 than the liquid the molecular 

 weight of which is to be de- 

 termined. (The boiling point 

 should not be less than about 

 25 higher.) The side tube d 

 is connected with a eudiometer 

 tube g standing over water. 

 The liquid in c is boiled and 

 heats the air contained in the 

 inner tube a. As soon as the 

 volume is constant, a fact which 

 is indicated by the constancy 

 of volume of air in the eudio- 

 meter tube g, the latter is filled 

 with water. The stopper is 

 then momentarily removed from 

 the inner tube a, into which is 

 rapidly introduced a weighed 

 quantity of the liquid under investigation (about 0'05 

 gramme), contained in a small bottle or bulb which it com- 

 pletely fills. This falls to the bottom of a, which contains at 

 the bottom some glass or cotton wool to break the fall, and 

 the liquid immediately vaporizes. In doing so it displaces 

 a certain amount of air in a, which enters the eudiomete* 

 tube g. The volume of air collected in this tube corre- 

 sponds with the volume of the vapour 'measured at the 

 temperature of ike air in tube g, and under the barometric 

 pressure prevailing at the time of the experiment. The 

 volume to which this amount would correspond at and 



Fig. Ua. 



