«0 G. J. BURROWS. 



For the sake of comparison the specific volume of the 

 pure solute in the liquid state was also determined. Benzo- 

 phenone is solid at the ordinary temperature, having a 

 melting point of 48°'5C. If, however, liquid benzophenone 

 be allowed to cool without shaking, it is possible to keep 

 it liquid for a considerable time below 30° 0. The volume 

 of the liquid benzophenone was determined by carefully 

 filling a five cc. pyknometer with the molten material, from 

 which air had been removed as completely as possible by 

 means of a suction pump, and then cooling carefully in the 

 thermostat and adjusting the volume in the usual way. 

 With a little care the liquid could be kept without crystal- 

 lising till after the adjustment, and the volume accurately 

 determined. One determination gave for the density of 

 liquid benzophenone, d 30 = 1*10231 whence v = 9072. A 

 duplicate experiment gave v = '9070. 



It will be seen from Table XVII that the specific solu- 

 tion volume is less in any of the solvents than the specific 

 volume of the liquid solute, indicating that the process of 

 solution is accompanied by contraction in each of these 

 cases. The specific volume is greater in benzene than in 

 either acetone or alcohol. This is in agreement with the 

 results obtained by Tyrer (loc.clt.) for other solutes in these 

 solvents. The values of v B for solutions in the benzene- 

 acetone mixture are intermediate between the values 

 obtained in the pure solvents. In the case of the acetone- 

 alcohol solutions, the values of v s are almost identical with 

 those for solutions in pure alcohol. In the preparation of 

 both of these "mixed solvents" there is practically no 

 change in volume. Thus in the preparation of the benzene- 

 acetone mixture, 145*3922 cc. of benzene at 30° O. were 

 mixed with 166*3833 cc. of acetone at 30° C, and the final 

 volume was 311*5620 cc. at 30° C. The total contraction 

 was only 0*2135 cc. which corresponds to a specific con- 



