20 H. Goadbyon making wet Preparations of Animal Substances. 
Description of the Slides. 
My peculiar wants have necessitated slides of larger size than 
that proposed for general adoption by the Microscopical Society 
of London; moreover, I had a collection of uniform preparations 
on slides of my size, long before that Society had existence. 
The slide I chiefly use measures when cut 3? inches, by 1gths: 
the glass should be the “ patent British plate,” before referred to, 
which being ground and polished on both sides is generally very 
flat: its substance varies from less than ,'gth to $th of an inch. 
2. 
j —T 
thick and rectangular 
in shape; on one of its 
long sides, a, is fasten- 
ed by means of pegs — 
or screws and glue another piece of mahogany, the guide board, b, 
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24 inches wide and # thick; this must be planed so as to be — 
true, as the front is to form a straight edge. By reference to the 
figure it will be seen that spaces have been cut out of the guide 
board, the use of which will presently appear, A flat rule or 
gauge should be made of mahogany, I! inches long and $ thick, 
the width to be ascertained as follows: mark out in card board 
a pattern of the slide intended to be used, apply the glazier’s dia- 
mond to a line indicating one side of the pattern and accurately 
measure the distance between the diamond and the other side, 
which will give the required width of the gauge. In other 
words, the gauge must be of the width of the pattern, less the 
“rake,” (or setting) of the diamond. In addition to gauges, a 
square is essential ; the most useful is of mahogany, one-fourth of 
an inch thick, with sides 64 inches long and solid, i. e., not open. 
he glass intended to be cut into slides should be placed on 
the cutting board, and if none of its sides have a true edge, & 
narrow slip must be cut off its entire length to form one. 16, 
straight side of the glass must now be brought against the guide 
board to ascertain if either of the sides, at right angles to the 
cut side be perfectly square with it; if not, it is only necessary 
to square one side: for this purpose place the side to be square 
so that it project a little beyond that part of the guide board 
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* This figure should be a +} are Sart Co ae dentiakce | 
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