510 Frederick Guthrie on some Thermal and 



Table LXIII. 



Volumes. 



On being mixed and brought 

 to the same temperature ! 

 (17° *6) which they had 

 before mixture, shrink to . 

 the below-given fraction of 

 the joint volume they had 

 before mixture. 



Chloroform. 



Ether. 



Per cent. 

 50-00 

 44-29 

 43 99 



43-83 



Per cent. 

 50-00 

 5571 

 5601 

 5617 



•0108869 



•0114783 



•0116756 (C,H l0 O, CHC1 3 ) 



•0115706 



The Table shows the great accuracy of which this method 

 is capable, and discovers a maximum contraction exceedingly 

 close to, if not at, the monomolecular ratio ; thus confirming 

 the result got by the cruder method of increased heat-tension, 

 § 270. 



The liquid solidifies to a white crystalline mass at a constant 

 temperature below 0°, which I shall give when I have deter- 

 mined it exactly. 



It seems, then, that ether and chloroform unite chemically 

 with one another to form the body C 4 H 10 O, CHC1 3 , a substance 

 which may be analogous in its composition with S 2 Ci 4 2(C 4 H 10 O) . 



Vapour-tension of Chloroform and Ether Mixtures. 

 § 272. The result of the experiments given above will make 

 it imperative to revise previous ideas about the vapour- tension 

 of mixed liquids. The following experiments with ether and 

 chloroform show how the vapour-tension varies with the com- 

 position. The a 1 sol ntely pure and dry substances were mixed in 

 various proportions by weight, and each mixture was introduced 

 into one of a series of perfect barometers in a room of uniform 

 temperature. The barometers stood in the same trough close 

 together. The readings were made with a cathetometer at a 

 distance of nine feet. The readings were made backwards 

 and forwards through the series three times. The atmospheric 

 pressure was made constant by adjusting the mercury in the 

 trough. About five grams of the liquid were introduced into 

 each tube, and in all cases enough, as shown by a rough mea- 

 surement and calculation, to ensure there being far more than 

 sufficient of each kind of liquid to supersaturate. After deter- 

 mining the mercurial depression, the liquid columns above the 

 mercury were measured, and their specific gravities assumed 

 to be those due to mixture without change of volume. This 

 is not quite true (see § 268). Further, it is assumed that the 

 liquid has the same composition before as after its introduc- 



