The record-union., 1895-03-07
TREMENDOUS PRESSURE
A Machine on the Hydraulic Princfp
but Using Oil Instead of Water

A Macnlno on the hydraulic Pfln C1ple,
but Using Oil Instead of Water.
The Listener" Of the Boston EUeni1q
transcript went the other day to see a
wonderful machine-a machine which is
not only a prodIgious and terrible piece
of enginery, but an allegory. 1t is called
a testing machine, and it is used to ascer-
tain the resisting power of various mate
rials. 1t is not content with finding out
that a Deam of oak, for instance, will
bear, without breaking, a pressure on
one spot of a hundred and sixty thousand
pounds; the beam must be utterly crushed
each time the test is made, and note must
/ be taken OF the exact weight that Law
upcn 1t at the moment of its final dissO-
luton. Day after day this great machine
heaVes and strains itself, and bears down
with slow and awful force upon some
tough beam or block OF wood; and
whether the timber is placed flatwise,
and needs say, but a paltry seyenty-tive
tons to crush it, or whether it is placed
endwise, like a pillar, and will hold up
| twice as much weight before it cries out
and gives up the ghost, it must yield just
the same, and surrender its pitiful,
crushed frame to be photographed and
studied and picked to pieces for the BEN
eft of science. That is all very interest
ing, you may say, but it is a mere piece
of the brute machinery; where is the alIe-
CORY that you told US of? That lies in the
thing by the force of which this mon
strous pressure is eXerted. It is oil:
nothing but suave, gentle, yielding, un-
resisting oil, the emblem OF softness and
agreeableness.
There Is certain piston in this mechan-
ism which, pressing against quantity OF
oil in q confined space, forces this oil
against another iron surface, which, in
turn, presses forward upon the tim Der. SO
that all this crushing power is exerted by
ia nH INN ~ TnN h hirnrr hut IL
watch the machine, even in the most ex-
citing moment Of the elimination of its
crushing force, you can not but be con-
sclOus that 1t is the Oil that is doing it.
The master stands over his great machine,
the pupils grouped about. 1t lies fiat
down on its great back, like giant brac-
ing his shoulders against a rock, to push
with his feet. The thing which he is
pushing against is beam OF seasoned
oak, about ten inches square, and the
thing with which he is pushing is another
and lengthwise square beam of oak, the
end OF which is directly against the side
OF the beam to be crushed. Off at one
side. apparently unconnected with the
machine, but in reality connecting with
1t, is an apparatus where there are levers,
compare Die to the throttle valve of a loco
motive, and gauge which registers accu-
rately the pressure that is being exerted.
A young learner stands at these levers,
says, Turn on more OIL" he moves a
lever, and the pressure rises. Seventy
thousand pounds, eighty thousand
pounds, it rises rapidly. The length
wise beam is sinking itself deep into the
side OF the victim timber, but this still
holds out bravely. The pressure rises to
ninety thousand-a hundred thousand.
The watchers all gather around the CEN
ter of the pressure in anticipation of the
catastrophe; the lengthwise timber is
squeezing into the solid oak. of the other
one as ones thumb might be driven into
a piece OF cheese.
But still it holds. Little by little the
power is turned on. The young man at
the gauge calls 'I20 000," "I3O, ,000," "I40,-
000," ''l50,OOO;" you hear the swapping of
a myriad OF tendons within the beam, and
all these sounds join in a sort of low,
buzzing roar or cry, which suggests an
elemental agony. One hundred and
sixty thousand pounds-the beam sinks
deeper into the flesh OF its victim-One
hundred and seventy thousand-"More
oiP' calls the master, and now the crackle
rises-the Iengthwise beam itself begins
to crack, and the other beam, yielding at
last, seems to go to pieces all at once, and
when the pressure Is removed it is taken
out, twisted, contorted, riven, pierced,
crushed.
1t is a useful service, after all, though it
seems'but an eXhib bition of the brutality
of mere mechanism, that the testing ma
chine and its bed OF oil have done, for
since the master began the work with it
he has proved that timbers will stand
only about half the weight which the ac-
cepted authorities said they would stand;
and by introducing more conservative
weighing of wood he has doubtless saved
many human lives from destruction by
the collapse of tim bered structures.