RESEARCHES ON THE VOLATILE HYDROCAISRONS. 



1 r, 



cooled in a mixture of ice and salt. The retort, which stood in a small copper bath 

 containing pounded ice, was charged with about 260ft c. of the liquid, which had been 

 previously cooled in a mixture of ice and salt. Temperature of the laboratory. liV C. 



Observations during the distillation : 



Temperature of the retort-bath, 



1 



44 



44 



boiling liquid, • 



u 



44 



vapor 



• 



0° 

 13°.5 



Temperature of the retort-bath, 



45 minutes later.* 2 



u 



.. 



.. 



LI 



boiling liquid, 

 vapor, 



0° 



1M 



1 9° • 



Temperature of the retort-bath, 



15 minutes later. 3 



.. 



.. 



44 



boiling liquid, 

 vapor, 



5 



1°.8 

 12°.6 



Temperature of the retort-bath, 



30 minutes later. 4 



44 



ii 



boiling liquid. 



44 



- 



vapor 



? 



3°.8 

 . 12°.4 



Temperature of the retort-bath, . 



30 minutes later. 5 



.. 



u 



a 



boiling liquid, 

 vapor, 



1 4°.5 



7°.3 



13°.8 



The apparent inconsistency that the temperature of the boiling liquid should be 



above that of the 



heating medium 



bath 



hich continued during 



first forty-five minutes of the experiment, is to be explained by the fact that there 

 was a long column of mercury, above the surface of the liquid, which was subjected to 

 the heating influence of the vapor. I would further remark that the gradual elevation 

 of the boiling-point, as indicated by the thermometer in the liquid, is also only appar- 

 ent, and is due to the gradual uncovering of the bulb as the liquid was distilled off. 

 At the close of the experiment only about one fifth of the bulb, which unfortunately 

 was a long one, was under the surface of the liquid. That this is the true explanation 

 is evinced by the fact that during the experiment not a drop of liquid was observed 



fall back 



the 



from 



ted condenser," although this was a tube 



th, and cooled to the temperature of 



I will 



now proceed to give my determinations of the boiling-points of various 



hydrocarbons, and of some of their derivatives, and then pass directly to consider the 



bearing of these 



the question concerning the increment of boiling-point for 



From this point the temperature of the retort-bath was gradually raised by means of a small gas-flame 



