238 



SCIENCE 



[N. S. Vol. XXVI. No. 660 



mining camps of Cobalt. Here small par- 

 ties were formed and visits were made to 

 many of the mines in the district. In the 

 evening the visiting members were the 

 guests of the Haileybury Club of Hailey- 

 bury, Ontario. Returning, the society 

 reached Toronto Tuesday morning. 



A summary of the many events of these 

 meetings appeared in the Toronto papers. 

 At the last general assembly a hearty vote 

 of thanks was extended to the local com- 

 mittee and the citizens of Toronto from 

 whom these many courtesies were received. 



The number of members in attendance 

 was 150, of whom 120 were visitors. The 

 next meeting will be held in Chicago, begin- 

 ning December 26. 



The following addresses were given be- 

 fore the general assembly: 



The Measurement of Chemical Affinity: 

 "Wilder D. Bancroft. 



Chemistry and Canadian Agriculture: 

 Frank T. Shutt. 



American Chemical Research: J. Bishop 

 Tingle. 



The Vagaries of Beryllium: Chables L. 



Parsons. 

 Defioccidated Graphite: E. G. Acheson. 



These addresses will be printed in full at 

 an early date. 



The following papers were read before 

 the society: 



PHYSICAL CHEMISTRY 



iW. D. Bancroft, chairman 

 Corrosion in Persulphate Solutions: J. W. 



TuRRENTiNE, Cornell University. 



Copper is dissolved in persulphate solu- 

 tions quantitatively. The loss in persul- 

 phate content of the solution is equivalent 

 to the copper dissolved. The corrosion of 

 copper in persulphate solution is therefore 

 analogous to the electrolytic corrosion in 

 sulphate solutions. Nickel, aluminum and 



iron also behave in persiilphate solutions as 

 one would expect from their electrolytic 

 corrosion when made anode in sulphate 

 solutions, i. e., nickel is but slightly at- 

 tacked in sodium persulphate, but more 

 readily so in ammonium persulphate ; alu- 

 minum is not attacked at all, and iron is 

 quite readily corroded. 

 Coefficient of Distribution: Livingston R. 



Morgan and H. R. Benson. 



The following results are reported : 



1. The molecular weights of alcohol in 

 ether and of acetic acid in ether are the 

 same as in water. 



2. The molecular weights of acetic acid 

 and alcohol in molten CaCl26H„0 and 

 molten LiNogSHaO do not vary with the 

 concentration. 



3. The molecular weight of alcohol in 

 benzene varies but slightly with the con- 

 centration. 



4. The coefficient of distribution is shown 

 to be independent of the heats of solution 

 of the substance in the two solvents. 



The Measurement of Chemical Affinity: 



W. D. Bancroft. 



The heat of reaction is not a measure of 

 chemical affinity ; but Gibbs has shown that 

 the electromotive force is a measure for 

 the case of completely reversible systems. 

 Cases which have been studied experimen- 

 tally are: precipitation of metal by metal; 

 allotropic forms of metals; amalgam cells; 

 stable and instable salts; metathetical re- 

 actions; oxidation and reduction cells; 

 light. When the gas pressures or the os- 

 motic pressures are known for a system in 

 equilibrium, it is possible to calculate the 

 work done against the chemical affinity by 

 displacing the equilibrium, provided the 

 equilibrium formula is known. This gives 

 a relation between the electromotive force 

 and the equilibrium constant, which has 

 been tested for: precipitation of metal by 

 metal; amalgam cells; stable and instable 



