3 o6 SCIENCE PROGRESS. 



is proportional to the corresponding diminution in viscosity, 

 and that the factor of proportionality is greater the greater 

 the molecular weight of the gas. 



According to Le Chatelier (149) the general law of the 

 solubility of a normal substance should be independent of the 

 nature of the solvent and should be given by 



0*002 log s— L/T + L// = o. 

 Here .9 is the number of molecules of substance in s-i 

 molecules of solvent, L and T the heat of fusion and melting- 

 point of the substance, and t the freezing-point of the 

 solution. 



Kiister (150) has attempted to find a convenient means 

 of applying Nernst's method of determining molecular 

 weights from diminution of the solubility. He uses as 

 solvents phenol and a saturated solution of common salt, and 

 finds how the solubility of the phenol is altered when 

 different substances are dissolved in it, the amount of 

 phenol dissolved by the salt solution being determined by 

 titration. The results are fairly satisfactory, but have no 

 pretensions to a high degree of accuracy. 



From observations on the partition coefficient, Kiister 

 infers that iodide of starch is not a compound (151), and 

 that when ether is absorbed by caoutchouc it exists partly 

 as double molecules, which become fewer the more dilute 

 the solid solution (152). By similar observations Schmidt 

 (153) concludes that dyeing is not a case of solid solution, 

 but is akin to absorption, and Jakovkin (154) studies the 

 dissociation of potassium tri-iodide in aqueous solution. 



In connection with colloidal solutions, Ramsden (155) 

 finds that if a solution of albumen be shaken it coagulates 

 and is only slowly soluble in water or salt solutions, 

 and differs from albumen coagulated by heat. The change 

 is not due to the chemical action of air. 



CHEMICAL MECHANICS AND AFFINITY. 



A detailed study of the mechanics of the reversible 

 gaseous reaction involving the formation and decomposition 

 of hydrogen iodide has been made by Bodenstein (156). 

 At atmospheric pressure the fraction of the total hydrogen 



