i88 



re;ports o^ investigations and projects. 



The range of temperatures over which the measurements of the pressure 

 of glucose solutions were made, in the first instance, was from 22.1° to 26.9°, 

 while the concentration of the solutions varied, by tenths, from o.i to i.o 

 weight-normal. At these temperatures, the solutions of glucose exhibited 

 pressures which were characterized in the following words : 



"It is clear, as it was in the case of cane-sugar, that glucose in aqueous 

 solution, at temperatures in the vicinity of 20°, exerts an osmotic pressure 

 equal to that which a molecular-equivalent quantity of a gas would exert if 

 its volume were reduced, at the same temperature, to that of the solvent in 

 the pure state. This rule holds equally well throughout all the concentra- 

 tions whose pressures we have measured, and the deviations from it do not 

 exceed the known but unavoidable experimental errors of the work." 



The justification for the conclusion stated above will be found in table i, 

 which gives a summary of the experimental results. 



Table i. — Determination of the Osmotic Pressure of Glucose. Series I, 1906. 



Summary of Results. 



H = i. Mol. Wt. Glucose = 178.74. Mean Mol. Wt. 180.08. 



A second conclusion which was drawn from the results involved the ques- 

 tion of the hydration of glucose in solution. The pressures observed were 

 found to be quite strictly proportional to the weights of glucose dissolved in 

 the unvarying mass of the solvent. This led to the conviction that, "in the 



