H.Goadby on mal king wet Preparations of Animal Substances. 231 
_ It has sometimes happened in boxes and upright vessels, that 
in time the ends have been pressed in by the pressure of the 
atmosphere: to prevent this contingency I soldered on to the 
sides at the top and bottom, a bar of glass represented by the dot- 
ted lines e, f, fig. 10—they are not shewn at the bottom. These ~ 
bars should be affixed to the sides before the vessel be made ; 
they will thus, if exact in their length, serve as a guide to the 
true position of the ends, and being ground with the top and bot- 
tom of the vessel when in the form of a hollow box, will give 
increased surface for the joints to be made at these places re- 
spectively. The bars at the top are very useful as a means of 
fixing the threads by which the preparation is to be suspended ; 
for this especial purpose I make four loops of the silk to be used 
(China three twist) and place two on each side of the vessel in 
the exact place they should occupy, and cement them firmly to 
the vessel by means of the bars—in mounting the preparation, I 
have merely to tie the threads which pass through it to these 
oops. In large vessels constructed on the principle lastly de- 
scribed, it is desirable to seal down the top glass with marine 
glue instead of the black cement. In this case the top glass 
ould be of the exact size of the outside measure of the box 
and two small holes should be drilled in it at opposite corners— 
one to let the air out while the vessel is being filled, by means of 
the other. The process is similar, in all respects, to the descrip- 
12. 
drill,” of which a figure is given. 
& tubular form, with one end 
adapted to the drill stock.* pe. 
‘The part of the glass to be drilled should be marked either 
With a scratch diamond or the point of a file. It is only neces- 
* The “bob” drill: a, the steel stock, 10} inches long perforated at ¢ with a round 
eye for the tramsbunioes of. conde the circular fy scentor the or on 
