Ralph, on Mounting Objects. 
35 
and place under it a piece of blotting-paper folded so as to 
support the central square inch only, where the hole is to 
be drilled ; have then prepared a steel instrument, called by 
watchmakers a broach, which is a five-sided, well-tempered 
tool, and sharpen it on a hone of some hardness (or on a 
a flint), so as to give it a three or more sided cutting end 
(this tool should be let into a cedar-pencil stick previously 
deprived of its lead and glued up again), dipping the point 
into oil of turpentine, place the end on the glass where the 
perforation is required, and endeavour to pierce it by a 
steady drilling movement ; the first effect will be to break off 
a small piece of the surface of the glass, or, if the operator has 
been too rash, to break it into pieces. Once the surface has 
been thus scratched, proceed with the drilling, always keeping 
a drop of turpentine on the spot ; in one or two minutes the 
drill should penetrate through to the other side. Some- 
times I place my finger behind the spot where the glass 
generally drops out in a small piece before the point of the 
instrument. A small hole being thus made, proceed next 
with a fine rat-tail file, dipped in turpentine, and drill on, 
and use larger sized files till the required opening is made. 
Mem. These are standing rules : Always begin with a re- 
cently sharpened broach; always keep it and the files wet 
with turpentine, and in screwing the rat-tail file through 
the glass always use it with an unscrewing movement, as if 
you were using a turnscrew to take out a screw, for the 
reverse movement immediately locks the tool into the glass 
and a leverage is used, and the glass shivers into pieces ; and 
never use the tool with any leverage against the edge of 
the glass. Two to three minutes more should suffice to 
drill through to the extent required (I have made myself a 
test tube- stand with holes large enough to hold the largest 
tubes made ; and there are six or eight holes in the piece of 
glass) ; and the required evenness of the edges of the hole 
may be brought out by using a carpenter^ s rose or counter 
sink, previously sharpened, and then hardened in the fire to 
flint hardness. This is also to be used with turpentine, and 
in ten minutes from the commencement of the operation 
almost any person may have one ready for use. The other 
cells are made in the same way, only larger sized files and 
flat files are used, according to the fancy or need of the 
operator; but the edges of these cells do not require the 
labour of polishing off, as the faults are not discernible when 
the cells are filled with balsam; and if made of uniform 
shape or outline, they will be found to be quite neat enough. 
A friend of mine here (an army surgeon) whom I have 
