358 Dynamic Theory. 



when cool, but on the slightest rubbing or stirring with a pointed in- 

 strument the part which is touched turns scarlet and this change of color 

 extends with a slight motion as if the mass were alive throughout the 

 whole group of crystals as far as they adhere together. " (Watts.) There 

 is a striking analogy in this action with that of fermentation, especially 

 when the latter is carried on through the agency of the insoluble fer- 

 ments, which are very rapid in their effects. A change of temperature 



FIG. 166. 



FIG. 156. Different forms of snow crystals. 



occurring during the formation of a crystal is evidently competent to dis- 

 turb its S3Tnmetry and often does it, and as an example above given shows 

 is even ableTo rebuild work on a new plan when once completed. Crystals 

 of Snow, as shown by fig. 156, take a. great number of forms, al- 

 though it is said that only one form usually occurs in any one storm, 

 presumably on condition that the electrical status remains the same. 

 A crystal must be recognized as an organism, and a live one at that, at 



