Contents xv 



PAGE 



Observations on the behaviour of mixtures, and particularly, 

 of isomorphous mixtures of salts 177 



The device of the elastic tank of uniform depth. It pro- 

 vides a standard of comparison between the chemical effect 

 of a dissolved salt and the mechanical effect of increased 

 pressure upon the boiling temperature of water. It furnishes 

 the extra load required to press on the surface of the pure 

 water in the tank so as to prevent ebullition at the temperature 

 at which a given weight of salt dissolved in the water would 

 produce the same effect. It furnishes the mechanical equi- 

 valent of the weight of salt, in so far as the raising of the 

 boiling temperature of water and the resistance to steam 

 pressure are concerned 178 



The specific properties of the dissolved salt are most pro- 

 nounced in its concentrated solution 179 



The mechanical experiment with the elastic tank represents 

 the chemical case where the increase of steam-tension neutral- 

 ised by the salt is proportional to the quantity of the salt. A 

 case of the use of the elastic tank is described fully . .180 



Demonstration of the identity of Blagden's Law with the 

 thermal law of mixture 182 



No. 5. THE SIZE OF THE ICE-GRAINS IN GLACIERS. (From 



Nature, August 22, 1901, Vol. LXIV, pp. 399-400) . . . 226 



This investigation was undertaken in order to ascertain 

 by actual observation the maximum size of the ice-grain in a 

 particular region of a particular glacier, and the gradation of 

 size of the other grains from this maximum downwards to 

 the minimum occurring in the block of ice dissected. In all 

 published descriptions it was admitted that the shape of the 

 ice-grain is irregular, but in dealing with the size of the grains 

 at any part of a glacier, the descriptions were frequently in- 

 compatible with the geometrical principle that, if the shape 

 of the grains is irregular, there must be grains of practically 

 all sizes from the maximum downwards, in order that the ice 

 may fill the space of a solid block. 



The blocks dissected were taken from the Glacier des 

 Bossons in the Chamonix Valley and from the Aletsch 

 Glacier at the Mergelin Lake 227 



Table I gives the weight in grammes of single ice-grains . 228 



Table 1 1 enables a view to be formed of the average size 

 of the grains in a block 229 



The action of solar radiation on glacier-ice is twofold : it 

 produces disarj: iculation and lamination . . 230 



