CHEMISTRY. 361 



Measurements have already been made in solutions ranging in con- 

 centration from 0.1 to 0.7 weight-normal. The observed ratios of 

 osmotic to gas pressure are practically identical for all concentrations, 

 as in the case of glucose; but they are all somewhat above unity, the 

 mean of all being 1.015. It would seem, therefore — speaking in terms 

 of the assumption that abnormally high osmotic pressure at low tem- 

 perature is probably due to hydration — that the temperature required 

 to dehydrate the solute completely is somewhat higher in the case of 

 levulose than in that of glucose. 



To the writer and to those associated with him in the study of osmotic 

 pressure, it has always appeared highly desirable that the scope of the 

 work should be extended to include a study of the vapor tension of the 

 solutions under investigation. The great advantages of such coordina- 

 tion are too obvious to require discussion, and it would have been 

 attempted long ago were it not for the fact that, until recently, we have 

 had no sufficiently precise and practicable method for the measure- 

 ment of vapor tension. All obstacles in the way of a simultaneous 

 study of the two phenomena — osmotic pressure and vapor tension — 

 have now been removed by Doctors Frazer and Lovelace, who, through 

 their long-continued cooperative efforts, have succeeded in developing 

 a thoroughly practicable method of high precision for the measurement 

 of vapor tension. They have already accumulated much reliable and 

 valuable data concerning some of the solutions whose osmotic pressure 

 had previously been studied. In the future, it is expected to continue 

 concurrently both hues of research, as nearly as possible. 



Noyes, Arthur A., Massachusetts Institute of Technology, Boston, Massa- 

 chusetts. Researches upon the properties of solutions in relation to the 

 ionic theory. (For previous reports see Year Books Nos. 2-13.) 



During the past year the investigations, referred to in previous 

 reports, on the equiUbrium relations of oxidizing and reducing agents 

 and on the electromotive forces of concentration-cells have been con- 

 tinued. 



The study of the equiUbrium between the metals bismuth and copper 

 and their chlorides BiOCl and CuCl in the presence of hydrochloric 

 acid has been completed with the assistance of Mr. M. Chow. The 

 experimental determination of the equihbrium conditions of the reac- 

 tion between plumbous chloride and chlorine has been continued by 

 Mr. E. W. Wescott, and an investigation by a colorimetric method of 

 the equilibrium between the manganate, permanganate, ferrocyanide, 

 and f erricyanide of potassium has been undertaken and carried through 

 with the assistance of Mr. A. W. Mudge. 



The investigation of the electromotive force of cells of the type H2, 

 HCl, Hg2Cl2+Hg has been continued by Mr. J. H. EUis. It may be 

 recalled that the purpose of this line of research is to determine the 



