103 



Per Pint. 

 Exp. 7. Evaporated 3 pints of solution. Residue, 0'79 = 0"263 grs. 

 Exp. 8. „ „ „ „ 0-78 = 0-260 „ 



Exp. 9. „ „ „ „ 0-78 = 0-260 „ 



Exp. 10. „ „ „ „ 0-77 = 0-257 „ 



Average, 0-260 per pint. 



Per Pint. 

 Exp. 11. Evaporated 6 pints of solution. Residue, 1-62 = 0*270 grs. 

 Average, 0*270 per pint. 



Twenty-four pints of distilled water thus dissolved 6-330 grains of 

 fluor-spar, so that the mean amount dissolved by one pint will be 

 0-2637 grains. One grain, therefore, of fluor will require 26-545 

 grains of water at 60° to dissolve it, or water, at that temperature, 



will take up .,„^,g th of its weight of that salt. 



The solubility here indicated must be considered great for a salt 

 hitherto reputed quite insoluble. It is still more soluble in water at 

 a high temperature, as the deposit left by warm solutions on cooling 

 shews. 



These facts will now be connected with the appearance of fluoride 

 of calcium in plants and minerals, as well as in mineral veins and 

 elsewhere; and may, perhaps, prove sufficient to explain these 

 hitherto somewhat perplexing phenomena. 



3. New Observations on the Glaciers of Savoy. Part I. By 

 Professor J. D. Forbes. 



This paper describes the remarkable changes which the glacier 

 of La Brenva, on the south side of Mont Blanc, has undergone be- 

 tween the years 1842 and 1846. 



It has increased to such an extent, that it has risen against the 

 opposing wall of rock on the side of the valley nearly 200 feet ver- 

 tically ; it has covered a large additional surface of ground, and ap- 

 pears to be approaching the moraines of 1818. The author de- 

 scribes the measures which he took for comparing its size at any fu- 

 ture period, and he cites some observations made by the Vicar of 

 Courmayeur (M. Guicharda), which plainly establish its continued 

 motion during winter. 



Professor Forbes then describes the remarkable development of 

 the veined structure which has occurred since his last observations 

 opposite to the promontory of rock on which the chapel is built, 

 which was formerly partially ruined by the glacier. He is of opi- 



