POPULAR SCIENCE REVIEW. 
ON THE MICROSCOPICAL STRUCTURE OF ROCKS. 
Br the Rev. J. MAGENS HELLO, M.A., F.G.S., 
PRESIDENT OE THE DERBYSHIRE MICROSCOPICAL SOCIETY. 
[PLATES CXYI. & CXVII.] 
I. 
S INCE the day when Ehrenberg, by means of the microscope, 
proved that certain rocks were almost entirely composed 
of the siliceous valves of minute organisms, little was done 
until very recently in the way of a systematic use of that instru- 
ment to solve the mysteries of geological science. And yet it 
stands to reason that there must he very much that is hidden 
to the eye in the minuter structure of rocks and minerals, that 
might he detected by means of the microscope, and which 
might throw a very considerable light upon the origin and 
history of such rocks and minerals ; much that might tell a 
wondrous story of the various forces that have been at work in 
building up the materials of which our earth is composed. 
Little, however, has been done in this country in such inquiries 
that has been made public. Besides two papers, one published 
as long ago as 1858 by Mr. Sorby, 44 On the Microscopic Cha- 
racter of some Crystals,”* and another on 64 The Microscope in 
Geology,” nine years later, by Mr. David Forbes, f there is, as far 
as I am aware, no additional information to he obtained upon 
the subject in our language, except such as may be gleaned from 
occasional papers in the 44 Journal of the Geological Society,” the 
44 Geological Magazine,” and one or two other scientific periodi- 
* 41 Journ. Geol. Soc./ ; vol. xiv. f Pop. Sc. Rev., vol. vi. 
VOL. XIV. — NO. LIV. B 
