of Substances in the Liquid and Solid Condition. 513 



indeed it is improbable that any hydrate would be insoluble 

 in a liquid which dissolves both the anhydrous substance and 

 water. The melting-points of the anhydrous and hydrated 

 substance were 40 o, 48 and 45°*42 respectively : Linnemann 

 gives 35°-38° and 46 c '5. 



Anhydrous pinacone superfuses considerably, and in the 

 case of the experiments Nos. 32 and 33, in which the liquid 

 substance was taken at an initial temperature of 44°, it did 

 not solidify till after it had attained the temperature of the 

 calorimeter : the heat evolved when it did solidify was noted 

 separately, and gave the two supplementary measurements 

 entered in the footnote to Table II. 



Octohydrate of Tin Tetrabromide. — The tetrachloride of tin 

 forms a tetrahydrate ; but as the anhydrous substance was 

 found not to solidify till —34°* 15, it was not a suitable 

 substance for the present investigation. The tetrabromide, 

 which solidifies at the higher temperature of 29 0, 36, was 



Fig. 1. — Freezing-points of SnBr 4 solutions. 



100 



Per cent. SnBr 4 . 



therefore examined in order to ascertain whether it also 

 formed a hydrate. The results of a series of freezing-points 

 of mixtures of it with water are given in Table IV. and fig. 1. 



