128 



OSMOTIC PRESSURE OF AQUEOUS SOLUTIONS. 



undeveloped state of the method at the time, all conspire to diminish 

 confidence in their precision. Nevertheless, they are doubtless much 

 more nearly correct than were the values obtained by correcting the 

 observed pressures for inversion. The ratios of osmotic to gas pressure 

 are all considerably above unity and are somewhat irregular, which 

 suggests — but does not prove — that osmotic pressure does not con- 

 form to the laws of Gay-Lussac and Boyle for gases. In a rough way, 

 the corrected pressures in Table 17 approach those which were obtained 

 later, after the method had been perfected ; and they foreshadow much 

 that was afterwards found to be true upon evidence which can not be 

 questioned. One of the more obvious conclusions to be drawn from 

 them — if they are credited with approximate accuracy — is that the 

 excellent molecular weights derived from Series I, and also from Series 

 II, by ascribing all loss in rotation to inversion, were entirely fallacious. 



Table 17. — Cane sugar, Series II. Observed osmotic pressures corrected for dilution 

 and the ratios of osmotic to the calculated gas pressures of the solute. 



Series III.* 



It has already been stated that in Series I and II no effort was made 

 to maintain specific temperatures throughout — that it was merely 

 sought to keep as constant as possible, for the time being, whatever 

 temperature the bath might have at the beginning of each experiment. 

 This was a necessary course as long as the means of regulating tem- 

 perature continued to be crude and to a high degree ineffective. 



*Measurements by H. N. Morse, J. C. W. Frazer, and W. W. Holland. 

 xxxvii, 425. 



Am. Chem. Jour., 



