284 Notice of Delafoste's Memoir of Crystallography. 



may henceforth rigorously apply invariable epithets, it will 

 be admitted that the form taken as the point of departure 

 must, in each of these bodies, possess a special molecular com- 

 position. 



Rigorously following up the principles adopted, M. Dela- 

 fosse endeavours to find, in divers substances, molecules 

 which should be in relation with their physical properties ; 

 but here it is difficult to materialise all the forms so as to 

 designate them by geometrical names, as he was able to do in 

 regard to the[cubical systems. M. Delafosse is of opinion, that, 

 after obtaining divers data, we can only arrive at a know- 

 ledge of the kind of molecular form of a substance, and that, 

 in order to obtain the true type, it is necessary to add to 

 it the atomic relations and chemical composition. He in- 

 timates that he has already obtained some results of this na- 

 ture, and he proposes to present them to the Academy in ano- 

 ther memoir. 



M. Beudant concludes his report by observing, that if it be 

 true, as has been alleged, that M. Delafosse's ideas are not al- 

 together new, and that the germs of them may be found in 

 different works, it ought to be added that these imperceptible 

 germs had remained wholly unproductive ; and if there be 

 any honour to be claimed, it is due to him who has rendered 

 them fruitful. The Academy agreed to his motion that M. 

 Delafosse's memoir should be inserted in the JRecueil des Sa~ 

 vants strangers. 



Observations on the Glaciers of Spitsbergen, compared with 

 those of Switzerland and Norway. By C. Maktens, M.D. 

 Member of the Northern Commission. (Continued from 

 page 177.) 



Causes of the annual Demolition of the Spitsbergen Glaciers, 

 — Dr Latta* positively affirms that the glaciers of Spitzbergen 

 always terminate at the margin of the sea. Scoresby t and 



* L. c. p. 102 and 2C0. t L. c. p. 97. 



