Page 40 - My FlipBook

use of the mallet than in the use ot hand pressure, although ;
the errors in the use of hand pressure are very frequent.
Among practitioners I find many who can take an instrument
in their hand with the pen grasp and make a pressure of
twenty pounds ; not so very many who will make a pressure
of twenty-five pounds, but a good many who can make a
pressure of only fifteen pounds ; and then again I find others
who cannot with all their force, big stout men, too, make a
pressure of ten pounds. Now, every dentist who cannot do
better than this with hand pressure should go into training.
It is simply a matter of training. Anyone with ordinary
strength can soon develop the ability to make twenty pounds
pressure and do it with ease. It is a matter of correctly
grasping the instrument and training the fingers to the work.
Curiously enough, I find that those who do not use heavy
hand pressure generally fail in their mallet pressure, also
they get apparently a similar result with mallet pressure that
they do with hand pressure, and are satisfied to stop with
that, seemingly.
Now as to the means of studying the mallet and of learn-
ing accurately of the force developed. The demonstration of
this is necessarily a roundabout process. I have here a con-
venient form of dynamometer and a variety of points. These
points are turned to a definite size and carefully measured
so as to know very accurately the size of the point. It is
first turned closely to size, then tempered and afterward
ground to size with an Arkansas stone, so that the edges
are perfectly sharp. Each one of these points used in the
dynamometer and the points used in this falling weight ap-
paratus have been made in that way. Now I take a piece of

paper of a definite kind that measures 3-1000 of an inch in
thickness, a pretty hard rolled paper, and place a block of
boxwood that has been faced on the lathe and made per-
fectly smooth, and I put pressure upon that. This particu-
lar instrument is twelve and one-half tenths, or one and a
quarter, millimeters, in diameter. Now, on this hard box-
wood block I will put on 43 pounds pressure. The paper is
not cut through. Now, I will move the block slightly and I
will put full 45 pounds pressure on it; the paper is cut
through and the piece left in the wood. A variation of a
single pound one way or the other will determine that. Now

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