THE PHYSICAL PROPERTIES OF AQUEOUS SALT SOLU- 

 TIONS IN RELATION TO THE IONIC THEORY. 



BY ARTHUR A. NOTES 



[Arthur A. Noyes, Professor of Theoretical Chemistry and Director of the Research 

 Laboratory of Physical Chemistry of Massachusetts Institute of Technology. 

 b. September 13, 1866, Newburyport, Mass. S.B. Massachusetts Institute of Tech- 

 nology, 1886; S.M. Massachusetts Institute of Technology, 1887; Ph.D. Leipzig, 

 1890; Assistant in Analytical Chemistry, Massachusetts Institute of Technology, 

 1887-88; student, University of Leipzig, 1888-90. Instructor in Analytical or 

 Organic Chemistry, Massachusetts Institute of Technology, 1890-94; Assistant 

 or Associate Professor of Organic and Theoretical Chemistry, 1894-99; Professor 

 of Theoretical Chemistry to date. President, American Chemical Society, 1904; 

 Member of the National Academy of Sciences; also of German Bunsen Society 

 for Applied Physical Chemistry, German Chemical Society, American Academy 

 of Arts and Sciences, etc. Written many books and articles on Chemistry.] 



IT is generally recognized that the further progress of physical 

 science will be greatly facilitated by a better systematization of the 

 knowledge already accumulated, and this is true in an especially high 

 degree of the newly developed branch of science in which this Section 

 is directly interested. It has therefore seemed to me that the most 

 valuable contribution that I could make toward the solution of the 

 present problems of physical chemistry in correspondence with the 

 aims of this Congress would be a formulation of the present status of 

 some of our knowledge relating to important classes of phenomena 

 which are being actively investigated, but which have not yet received 

 a final interpretation. It was my original hope to discuss several such 

 classes of phenomena; but the effort involved in the collation and 

 criticism of the available data connected with the problem which was 

 first studied forced me to confine my attention to that alone. This 

 problem concerns the physical properties of aqueous salt solutions in 

 relation to the ionic theory. This is the subject which I shall attempt 

 to present to you : I hope that its importance and the greater definite- 

 ness that can be given to its treatment may compensate for the some- 

 what limited scope of this paper. 



Permit me to say in advance that I have studied this subject 

 primarily from an empirical standpoint, and that it will be my aim to 

 present to you a series of generalized statements of the experimental 

 results, formulated in such a way as to show their relation to the im- 

 portant hypotheses connected with the ionic theory. Unfortunately, 

 it will not be possible in this address to reproduce, or even fully refer 

 to, the data upon which these conclusions are based a defect serious 

 in a work of this kind, which will be remedied in a subsequent pub- 

 lication. I shall, however, try to show the general character of the 

 evidence for each conclusion and the degree of accuracy within which 

 it has been confirmed. I wish to add that I have been most ably 



