THE MICROSCOPE. 3 | 
thickness. This is cemented to the slide with mucilage. A paper 
‘front ” must be used, for, if a varnish is used it will defeat the object 
of the paper cell. If sweating should occur in one of these cells, 
which only happens in exceptional cases, it is only necessary to lay 
the slide on the warm table and apply a gentle heat. As soon as the 
blotter is dried out it will absorb all the moisture that may be in the 
cell. 
For balsam mounts I use brass curtain rings, cemented to the 
slide with gold size, and well varnished on the inside with the same. 
For dry mounts which are not liable to give off moisture, I 
employ wax cells. They are quickly made and are very strong. 
My method is as follows: A piece of single-thick sheet-wax, such 
as is employed in making artificial flowers, is put on the centre of a 
slide and held there by pressing the ball of the thumb against it. 
The heat of the hand is just sufficient to make it adhere. When the 
first piece is firmly attached, which can be told by the absence of air 
bubbles when viewed from below, a second piece can be added and 
secured in the same manner, In this way cells of any depth can 
be made. When the wax is of the required thickness the slide is 
placed on the turn-table and with a sharp scalpel a cell is “turned” 
out of the mass, as a turner fashions a bowl in his lathe. A damp 
cloth on the end of the finger or a small stick, is used to clean the 
glass inside the cell. The wax must be well varnished, or the 
volatile portions will escape and collect in fine beads on the under 
surface of the cover. Wax cells made in this way seldom become 
loosened from the slide, even when roughly handled. 
Glycerin mounts I put up in glass cells. As these should be 
attached to the slide with the solid marine glue, it is better to get them 
ready prepared. I secure the covers with shellac, as it is less liable 
to run in than white zinc. These mounts afterward receive a coat of 
white zinc as a safeguard. 
You will notice from these remarks that I am an advocate of 
the wax cell and shellac varnish. The merits of the latter are now 
pretty generally known, and if once used it is not apt to be discarded, 
It must not be trusted to alone, as it will not stand sudden jars. 
The wax cell is still a disputed subject. I know they are liable to 
sweat, but I think I can safely hazard the statement that not one dry 
mount in fifty, not put up in an absorbent cell, will show an 
unclouded cover after a few years. Objects of the mineral kingdom 
alone do not give off vapors. 
Again, we must not lay the defects of the cover-glass itself 
to this cause. If you examine carefully a number of cover-glasses, 
