veniently in a three-jaw chuck by means of the
handle.

Mr. Shenstone recommends a lubricant composed of camphor dissolved in
turpentine for general purposes. With the object of obtaining some
decisive information as to the use of this lubricant, and to settle
other points, I made the following experiments. Using an old
three-cornered French file, I chipped off the point and adjusted the
handle carefully. I also ground out the file marks near the point,
without hardening the file in mercury. Using kerosene and turpentine
and camphor, I began to bore holes in a hard bit of 3/32 inch window
glass.

Each hole was bored to about one-eighth inch in diameter in four
minutes with either lubricant. After hardening the file in mercury
and using kerosene, I also required four minutes per hole. After
mounting the file in a lathe which had been speeded to turn up brass
rods of about one-half-inch diameter, and therefore ran too fast, I
required one and a half minutes per hole, and bored them right
through, using kerosene. On the whole, I think kerosene does as well
as anything, and for filing is, I think, better than the camphor
solution. However, I ought to say that the camphor-turpentine
compound has probably a good deal to recommend it, for it has survived
from long ago. My assistant tells me he has seen his grandfather use
it when filing glass.

I beg to acknowledge my indebtedness to Mr. Pye, of the Cambridge
Scientific Instrument Company, for showing me in 1886 (by the courtesy
of the Company) the file method of glass-boring; it is also described
by Faraday in Chemical Manipulation, 1228.

It is not necessary, however, to use a file at all, for the twist
drills made by the Morse Drill Company are quite hard enough in their
natural state to bore glass. The circumferential speed of the drill
should not much exceed 10 feet per minute. In this way the author has
bored holes through glass an inch thick without any trouble except
that of keeping the lubricant sufficiently supplied. For boring very
small holes watchmaker's drills may be used perfectly well, especially
those tempered for boring hardened steel. The only difficulty is in
obtaining a sufficient supply of the lubricant, and to secure this the
drill must be frequently withdrawn.

My reason for describing the file method at such length is to be found
in the fact that a Morse drill requires to be sharpened after drilling
glass before it can be used in t