CRYSTALLIZATIONS. 



115 



Fig. 181. 



were more or less broken, on account of the fragile nature of the ashy film ; but 

 many were preserved entire, and . exhibited in the field of view, the crystalline 

 network of the figure. With- 

 in the compartments formed 

 by the chains of crystals, dark 

 masses are beheld, which are 

 crystals of a larger size. The 

 small crystals measure in 

 length one-two thousandth part 

 of an inch, and the larger one- 

 seven hundred and seventy- 

 fifth part of an inch. 



Amid the starch globules of 

 potatoes and in the outer coat- 

 ing of the bulb of the onion, 

 crystals have likewise been a 

 found, differing in form from 

 all the preceding. In figure 182 

 the thin coating of an onion is 

 delineated as it appears when 

 magnified. This tissue is di- 

 vided up into cells in which 

 the crystals are formed. Their shapfc is that of a right square prism, and, in 

 length, they measure one-eight hundred and thirtieth part of an inch. 



Fig. 182. 



