H, Goadby on making wet Preparations of Animal Substances. 27 
of all sizes, and chiefly use one of 1,%,ths diameter, cut out of a 
square of glass 13 inch full, outside measure. 
ith my large slides such a cell enables me to preserve great 
uniformity in my preparations, affords abundant space for the 
transmission of light around the object, holds a sufficient quantity 
of preserving fluid, and the squares can be cut with the same 
gauge used for the slides themselves. The length of the drill 
may be from 1 inch to 14 long, and made to run true in a lathe. 
The squares of glass being all of the same size, I cement a num- 
ber of them together with the marine glue, so as to form a pile 
of from one inch, to two inches high. 
Where a Jathe is used, it is important to face the pile of squares 
with something that has been already perforated with a hole the 
size of the drill, to enable the latter to enter at once upon its work, 
and prevent the stratching (and spoiling) the first cell. For this 
purpose, brass perfectly flat, can be used; but a better thing is a 
square of plate glass, one-fourth of an inch thick, already perfo- 
me by the same drill, and this should be kept for the purpose 
alone. 
_ The copper drill is to be charged with fine, sharp cutting sand 
and water, and the block or pile of glass squares applied to it, 
and gradually pressed up by the tail spindle of the lathe, while 
the drill should revolve at a moderate, but not a rapid rate. When 
a number of cells are drilled, they can be easily separated from 
the block by placing the outer cell downwards on the iron plate 
and applying the spirit lamp: they can be removed one after the 
other with great rapidity, until only undrilled glasses remain, 
and to these other squares may be added if necessary. 'To make 
an oval cell, two round 5. 
holes (fig. 5, a, b,) must 
be drilled so as to inter- 
Sect each other; . their 
proximity to be deter- 
mined by the length of 
the oval required. The 
pieces that remain. on 
each side, c,d, can be 
to the lathe, charged with sand and water on the edge, and it 
. There is another excellent method of cutting either round or 
bad 
Pe 
