376 



Dr. C. R. Alder Wright, 



[Jan. 28, 



regards the lighter fluid ; thus the same mixture yielded the following 

 figures, according as the temperature at which the mass was main- 

 tained during the period of agitation and standing lay near to 20, 

 16, or 4 respectively ; whilst at temperatures above 25 a single 

 homogeneous fluid was formed, not separating at all until the tempe- 

 rature was slightly lowered. 



In order to obtain numbers as nearly as possible comparable with 

 one another and with those previously described in Part IV (all 

 of which were obtained at temperatures pretty close to 18), 

 the mixtures employed were examined at temperatures somewhat 

 above, and also at a little below 18, in such fashion that the average 

 numbers obtained with each mixture should represent the mean com- 

 positions for an average temperature sensibly = 18. The following 

 average numbers were thus obtained in three such cases : 



Fig. 1 represents these values, together with those previously 

 described in Part IV, the tie-lines numbered 1 to 8 being those pre- 

 viously described, and those marked 9, 10, and 11, the above three 

 sets of average values respectively. The line db is the tie-line uniting 

 the two points obtained as above-mentioned with one mixture 

 examined at 4 C., obviously belonging to a critical curve lying 

 outside the curve for 18. The point P indicates a mixture of chloro- 



