308 SCIENCE PROGRESS. 



of inversion of sugar, Noyes and Clements (161) infer in 

 a similar way that hydrogen potassium tartrate when dis- 

 solved yields a certain amount of free acid. The inter- 

 action of stannous chloride and ferric chloride has been 

 shown by Kahlenberg to follow the law of mass action 

 (162). 



A reaction in a heterogeneous system has been studied 

 by Carrara and Zoppellari. They find that on stirring 

 water and sulphury! dichloride by blowing air through the 

 mixture, the reaction is of the first order, and the law of 

 mass action is obeyed just as in a homogeneous system. 

 The velocity is the same if decinormal potash solution be 

 used, hence it is concluded that the water and not the 

 potash effects the decomposition. 



The affinity coefficients of a large number of bases have 

 been obtained by Bredig(i64) fr° m observations on con- 

 ductivity. The results show that of organic bases the 

 quaternary are the strongest, and the ternary the weakest. 

 The bases of P, As, Sb, S and Te are very strong, those 

 of Sn and Hg are very weak. In the case of metameric 

 diamines the base is the stronger the further the amido- 

 groups are apart in the molecule. 



A curious method of determining the affinity of feeble 

 acids is due to Wood (165). It depends upon the inhibitory 

 action which they exert on the velocity of hydrolysis of 

 starch by diastase. Ostwald thinks the method may be 

 useful in the case of feeble bases. 



Linebarger (166) has described a method for measuring 

 small dissociation-pressures like those of hydrated salts. 

 The salt is brought into contact with ether and the amount 

 of water given up to the ether determined by the rise in 

 its boiling-point. The concentration of the water in the 

 ether is thus obtained, and the dissociation-pressure of the 

 salt is equal to the partial pressure of water in the vapour of 

 a solution of this concentration. References to several new 

 methods of determining transition temperatures are given on 

 P- 3I9- 



Continuing his previous experiments, Lea (167) found 

 that on subjecting several easily reducible salts of metals, 



