2 2) See 
ae ae 
On Dimorphism of Arsenic, Antimony and Zinc. 195 
mamillary concretions of zine, which are frequently deposited on 
the cooler portion of the retort during the process of distillation 
might readily be mistaken for pentagonal dodecahedrons without 
any exact measurement of angles, and secondly that this form 
which is characterized by a peculiar law of symmetry, has never 
been observed unless this case is an exception, on any metallic 
erystals. The question might readily be settled by a reéxamina- 
tion of the original specimen and it is to be hoped that, if they 
still exist, such an examination will be made. 
I al 
zing the series of crystals as well as the alloys in 
a 
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