Page 41 - My FlipBook
P. 41
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we know the. force necessary to cut the paper with this par-
ticular instrument point. (Now, I know that it is exceedingly
difficult for you to see these experiments from your seats.
T wish I could have every one of you come down here and
look over these individually, but you see clearly that that is
impossible, but I will ask the officers of the class to come
down and stand here with me and see them.)
Now I can repeat this experiment with a falling weight
with the wood block resting upon this heavy anvil, in which
the pressure can be repeated very accurately. I have here
a number of mallets designed for use in this falling weight
apparatus. This mallet weighs one ounce. I move this table
up on this standard to 675-1000 of a foot. (I have on this
standard three scales—one is in hundredths of a foot, an-
other is in millimeters, and another is in inches—so that I
can use any of these that I please.) Now I will take the
same block and the same piece of paper and the same point,
and I will let the weight fall, making what appears to be a
slight blow, and you will see that I have produced a result
precisely similar to that produced with the dynamometer.
Here I can again measure the number of pounds and know
just what number of pounds is necessary to produce this
particular result, and get it so definitely that in some of the
lines of experiment that I have carried through, using twenty
different conditions of weights, heights, etc., the variation in
the experimental results would not exceed one pound. Fur-
thermore, although the mathematics of the subject has not
yet been at all sufficiently made out, I am able, when finding
the height of the fall of any definite weight necessary to
produce a pressure of any given number of pounds, to figure
the height of the fall of any other weight to produce this re-
sult—the half-ounce, two-ovmce, three-ounce, four-ounce or
any other definite weight, or to calculate the pounds pressure
any of these weights will develop when falHng from a given
height.
We have here another instrument, the Hiptodynamometer
with which we may again measure these results with the hand
mallet or with falling weights. I take this mallet and strike.
A pencil flies forward and makes a record of the blow, not
of the pounds, but of the impulse given by the blow. Mind
you, that is not a record of the pounds, but we may find the
27
we know the. force necessary to cut the paper with this par-
ticular instrument point. (Now, I know that it is exceedingly
difficult for you to see these experiments from your seats.
T wish I could have every one of you come down here and
look over these individually, but you see clearly that that is
impossible, but I will ask the officers of the class to come
down and stand here with me and see them.)
Now I can repeat this experiment with a falling weight
with the wood block resting upon this heavy anvil, in which
the pressure can be repeated very accurately. I have here
a number of mallets designed for use in this falling weight
apparatus. This mallet weighs one ounce. I move this table
up on this standard to 675-1000 of a foot. (I have on this
standard three scales—one is in hundredths of a foot, an-
other is in millimeters, and another is in inches—so that I
can use any of these that I please.) Now I will take the
same block and the same piece of paper and the same point,
and I will let the weight fall, making what appears to be a
slight blow, and you will see that I have produced a result
precisely similar to that produced with the dynamometer.
Here I can again measure the number of pounds and know
just what number of pounds is necessary to produce this
particular result, and get it so definitely that in some of the
lines of experiment that I have carried through, using twenty
different conditions of weights, heights, etc., the variation in
the experimental results would not exceed one pound. Fur-
thermore, although the mathematics of the subject has not
yet been at all sufficiently made out, I am able, when finding
the height of the fall of any definite weight necessary to
produce a pressure of any given number of pounds, to figure
the height of the fall of any other weight to produce this re-
sult—the half-ounce, two-ovmce, three-ounce, four-ounce or
any other definite weight, or to calculate the pounds pressure
any of these weights will develop when falHng from a given
height.
We have here another instrument, the Hiptodynamometer
with which we may again measure these results with the hand
mallet or with falling weights. I take this mallet and strike.
A pencil flies forward and makes a record of the blow, not
of the pounds, but of the impulse given by the blow. Mind
you, that is not a record of the pounds, but we may find the
27
