22 THE NORTHERN MICROSCOPIST. 
hexagonal plate, and Fig. 2 is a more complete crystal of the same 
kind. 
The crystals assume various forms ; prisms and hexagonal plates 
are plentiful; while the “star” or “snow-crystals” are not so com- 
mon. Many of the plates and prisms form exceedingly beautiful 
objects for the polariscope: not only do the crystals themselves 
polarize, but the glass immediately surrounding them often 
polarizes likewise to some extent. 
The illustrations contained in this preliminary note have been 
prepared by photographing the crystal with the aid of a quarter 
inch objective ; the collodion film was then transferred to the wood 
block, from which picture the engravers worked. W.D.H., G.Z.D. 
