CHEMISTRY. 



251 



The first question has been definitely answered. The temperatures at 

 which the unit ratio of osmotic to gas pressure is reached are as follows : 

 For the 0.1 weight-normal solution, 30 ; for the 0.2, 50 ; for the 0.3 and 

 0.4, 60 ° ; for the 0.5, 0.6, and 0.7, 70 ; for the 0.8, 0.9, and 1.0 solutions, 8o°. 



The answer to the second question is still incomplete, since we have not 

 yet measured osmotic pressure at temperatures above 8o°. All the evidence 

 thus far obtained is, however, of an affirmative character — to the effect, 

 namely, that the unit ratio once reached is maintained at the higher tem- 

 peratures. The following is an epitome of the results obtained to date : 



The first section of the above table contains the osmotic pressures which 

 were found, while in the second section these pressures are expressed in the 

 form of ratios of osmotic to calculated gas-pressure. The heavy, straight, 

 horizontal lines in the table separate the groups in which the ratio of osmotic 

 to gas pressure is constant and above unity for each concentration from 

 those in which the ratio is either unity or is diminishing, with rising tem- 

 perature, in the direction of unity. The broken line serves to indicate the 

 temperatures at which the osmotic and calculated gas-pressures of the vari- 

 ous solutions become equal. The blank spaces in the tables indicate the field 

 within which the investigation is still unfinished. 



