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On the Crystallization of Ice, and of Veins of Ice in Ice. By 

 Professor Hessel. 



t OR some time past I have been occupied with observations on 

 the different forms of crystallization. The crystallization of 

 water under certain conditions, induced by artificial means, 

 formed also the subject of my inquiries. I shall here briefly 

 detail one of my experiments, which I have repeated frequently 

 of late, as I reckon it not unimportant for the doctrine of veins, 

 whose different modes of origin can, in my opinion, only be sa- 

 tisfactorily explained by collecting as many examples as possible 

 of the formation of veins and vein-like masses since the commence- 

 ment of historical epochs. So that we have then only to inquire 

 whether this or the other vein, or assemblage of veins, bears most 

 resemblance to lava-veins in lava, to veins which may be con- 

 sidered as canals filled up by mineral springs of some sort or 

 other, to fissures filled by sublimations, to fissures which have 

 been the outlets for alternate streams of fluid or elastic matters, 

 and which have been gradually closed by the deposition of solid 

 matters, or to fissures which have been filled by infiltration from 

 above, &c. ; or whether these veins are to be viewed as the result 

 of the contemporaneous congelation (crystallization) of two or 

 more heterogeneous masses, one of which has filled fissures in 

 the other, but which have never been in reality open. 



Upon this supposition every experiment on the origin of vein- 

 like masses, however insignificant it may appear, must be con- 

 sidered as an augmentation of our resources for the elucidation 

 of the origin of those veins which have not been observed by 

 man, so that this communication is of interest not merely to the 

 crystallographer but also to the geognost. 



I set aside, in a warm room, a mixture of fine clay and water, 

 in which the latter was somewhat in excess, so that the thin mud 

 could be easily stirred about with a fine hair-brush. Upon 

 resting for some time it divided into two portions, the under- 

 most of which consisted of moist clay, and the upper and least 

 considerable of clear water. During the cold days which we 

 had in December (5° — 10° F.), I exposed the mixture after 

 agitation to crystallization or freezing. Crystallization did not 



