Microscopical Society of Victoria . 
57 
In mine, once on the turn-table is all required; by his process, 
three or four times he seems to recommend ; by mine, no varnish 
is required — by his, the covers are varnished or cemented to the 
rings. 
On Covering Fluid Mounts to avoid Leakage or Running-in. 
By W. M. Bale. 
[Read September 25th, 1879.] 
In mounting objects in fluid one of the principal requirements 
is to fasten the cover of the cell securely, so as neither to permit 
leakage nor running-in of the cement. There are two methods 
described in most of the text-books, both of which have 
disadvantages that impair then* utility to a greater or less extent. 
The first, which is recommended by Davies, is to paint the cell 
on its upper surface, and the cover on its under surface near the 
margin, with thin coats of gold size or other cement, and to press 
down the cover, forcing out the superfluous fluid in doing so, 
when the varnished surfaces of the cover and cell, not being 
affected by the fluid, will adhere together. It is a serious defect 
in this process that it will not permit of sliding the cover to one 
side after fixing it, if, as frequently happens, it should be necessary 
to re-adjust the position of an object which may appear, on 
examination under the microscope, to require alteration. 
Moreover, thin pellicles of fluid frequently remain between the 
cover and the surface of the cell, preventing the perfect adhesion 
of the cement, and allowing the ingress of air. The other process, 
which is preferred by Dr. Carpenter, is to simply apply the 
cover upon a cell a little larger than itself, and when the outside 
is dry to paint it round the margin with varnish, giving several 
coats as they successively dry. This has the disadvantage of not 
holding the cover sufficiently firmly to the cell, and of being 
peculiarly liable to “ running-in.” 
These evils are to a great extent obviated in the following plan, 
which is especially adapted to cells of any thickness not greater 
than that of ordinary card or thin glass. An essential point 
consists in reversing Carpenter’s rule, and using a cell smaller than 
