CHEMISTRY — MORSE, XOYES. 221 



every concentration, decidedly smaller than between o° and 25° ; i. e., that 

 the solutions apparently become more dilute as the temperature rises from 

 some point between 25° and 30°. It is now to be ascertained, for each con- 

 centration, at what temperature this apparently progressive dilution reaches 

 a maximum, and whether the maximum is in every case that which gives the 

 unit ratio of osmotic to gas pressure. 



The author of this report has had, during the past year, the uninterrupted 

 cooperation of Drs. W. W. Holland and C. N. Myers. 



Mr. J. L. Carpenter has carried out an elaborate investigation of a number 

 of manometers of a new form which it is proposed to use in the future. 



Mr. G. Cash has made a number of preliminary determinations of osmotic 

 pressure at the higher temperatures. 



Mr. A. D. Holmes has investigated the ferro-cyanides of zinc and cobalt 

 with reference to their semi-permeable character, and has proved that the 

 latter is serviceable for the measurement of osmotic pressure, while the 

 former is worthless for that purpose. 



Mr. J. L. McGhee has investigated the ferro-cyanide of nickel, and has 

 shown that, as a membrane, it is probably superior to the ferro-cyanide of 

 copper. 



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

 chusetts. Grant No. 706. Researches upon the physical properties of 

 aqueous solutions in relation to the ionic theory. (For previous reports 

 see Year Books Nos. 2-9.) $3,000 



The following lines of research have been pursued during the past year : 

 With the aid of Dr. W. C. Bray, Dr. W. D. Harkins, and Mr. W. J. Win- 

 ninghoff, new determinations of the effect of salts on the solubilities of other 

 salts have been made, and the experimental material obtained in this labora- 

 tory during the preceding years has been discussed from a theoretical stand- 

 point and prepared for publication. The results show that the ratio of the 

 activity to the concentration of univalent ions decreases slightly, and the 

 corresponding ratio for the un-ionized portion of the salt increases markedly, 

 with increasing concentration of the salts or ions in the solution ; and there- 

 fore, that the deviations from the theoretical dilution law exhibited by uni- 

 univalent salts arise mainly from the abnormal influence of the un-ionized 

 substance. The influence of the common bivalent ion on the solubility of 

 unibivalent salts is shown to be so extremely abnormal that the activity of 

 such ions can not be even roughly proportional to their concentrations. In 

 other words, the solubility-product principle based on the law of mass-action 

 is shown to lead to utterly erroneous results when applied to a moderately 

 soluble unibivalent salt in the presence of another salt having the same bi- 

 valent ion. It has been shown that this remarkable result is probably due to 

 the presence of intermediate ions (such as AgS04~", ClPb+) in considerable 

 proportion in the solutions of such salts. 



