LETTERS TO THE EDITOR. 19 
to be cut so thin as igneous rocks, and they may also be left on the grinding- 
slide, which will not be scratched. 
III. Preparation of sediment and sand. These are prepared in two ways: 
1. Sprinkle a little on the sediment evenly on a slide, and run a little balsam 
and benzol over it gently, then cover with thin glass. 2. Moisten a slide with 
weak gum-water, let it dry, breathe on it, and sprinkle the sediment as before. 
When dry, mount with balsam. 
To prepare some sandstones for mounting in this way, crumble a fragment 
either with the finger or with a stiff brush, and mount in balsam. In this way, 
and by the aid of polarised light, much may be learned of the composition and 
origin of sediments, and also of rocks, such as sandstones, which are too friable 
to permit of sections being made. 
EE TIERS: £0: Git EDITOR. 
DEAR Sir, 
I learn with pleasure, that you have projected a scheme for 
a journal, which will give fixity and /ocus to the many instances of 
industrious and careful observation on microscopical matters that 
are constantly made, but, in the majority of instances, nowhere 
permanently recorded. Iam confident that if this be judiciously 
done, it may prove a great gain to microscopical manipulation, and 
methods of research, at least. It will have its influence on the 
structure of the instruments also, and will be a means of suggesting 
modes of working to serious and skilful labourers. I write of course 
mainly of the North of England, to which your proposed journal 
specially applies, and of which I have the most accurate information. 
For twelve successive years I have been closely connected with an 
important Northern Microscopical Society ; and during that time 
many valuable papers have been read, and suggestions given, by 
several of the members, which either have never been recorded, or 
if so, only as being summaries; and in the pages of a scattered 
literature. It is true, The Royal Microscopical Society has, of late 
years especially, offered excellent facilities for the publication of 
all observations of value, and all ingenious inventions in methods 
and appliances. But my experience teaches that there are many 
valuable fragments remaining that only such a journal as you pro- 
pose wil be likely to secure: and although its mission may not be 
—does not aim at being—the highest, yet it will pocut towards 
even this, and serve an eminently useful purpose. I wish you all 
the best elements of success in your work. 
Truly yours, 
W. H. DALLINGER. 
SHEFFIELD COLLEGE, 
Sheffield, Nov. 18, 188o. 
