Eureka daily sentinel. [volume] (Eureka, Nev.) 1871-1887, 1884-09-06
TESTING A HAIR's THICKNESS.
A Delicate Machine I'm the Post.
Office Departtne nf and Its Use.

A Delicate Machine fn the Post.
Office Departune emit and Its Use.
A curious little machine in the Office Of
the Chief of the Stamp Bureau Of the Post
office Department, Washington, d. c., is
the cause Of the cancellation of the con.
tract of the New England firm with the
Government for furnishing envelopes TO
the Postofice Department. 1t is q queer
looking continuance, 9 cross between q set
Of butchers scales and ordinary grocers
scales, or rather q combination of the two.
There is q large dial, like the face Of q
clock, with q little hand that flies around
the face pointing to the figures at the side,
which are arranged like the figures on the
clock face, with little dots between. "You
see three dots ?' said the gentleman in
charge, inquiringly. 'Well, the space be-
tween those indicates one sixteen thou
sandth Of an inch. Getting 1t down pretty
fine, isn't it2 You see this movable piece
Of iron here which comes down with q
smooth surface upon this other solid sur-
face2 Well, the raising or lowering Of
that moves the pointer which runs round
the dial. To test the thickness of a sheet
of paper we simply place it between this
movable piece and the solid surface below,
and when the movable piece of iron comes
down upon the paper the hand registers
the true thickness Of the paper. Delicate
instrument? Well, / should think 30.
Just give me a hair from your head, will
you? 2"
Then he took q hair and slipped it deity
between the movable pieces. The hand on
the dial followed the motions of the screw
until it stopped at the figures 30. "Just
twenty sixteen-thousandths OF an inch in
diameter" he said. Nov let me try q hair
from your mustache. They are generally
much larger, especially If you have not
been in a habit Of shaving" He took up
pair Of scissors, and clipping of q hair
from the mustache, placed it in position.
The hand stopped at so. Fifty sixteen
t~housandths Of an inch thick" he said.
THAT shows the effect OF shaving. I
measured a hair from the hand of q gen.
tleman q few minutes ago which was
forty sixteen-thousands thick, but those
in his mustache were precisely the same
thickness, the reason being that he had
never shaved. Yes, that is the machine
that proved that the firm making our en-
velopes was not fulfilling its contract" he
said, as he fell back admiringly.
"By this dial we can see just the thick
ness. By this lever, which 10 very much
like a pair of grocer's scales, we can tell
just what presumes the paper will stand.
You see we have two other movable pieces
of iron here, with q hole entirely through
both and a plunger which passes through
that hole. Well, we put the paper be-
tween those pieces, which when they are
pressed tightly together by this lever, hold
it firmly. The plunger, which passes
through the opening in the two pieces Of
iron, encounters this paper thus firmly
held. To know what the pressure is we
have the plunger attached 10 q scale lever
with q weight attached. like an ordinary
pair of scales, and by moving this weight
out along the lever until the paper breaks,
of course we can see just what the weight
is that makes IL break. See2 Very simple
after you understand it. Well, that ia
what the pspermskers thought after they
had lost an $50, 900 contract by it. 1t WAS
q new thing to them, but they scknowl-
edged that they were beaten when they
saw t."
This delicate instrument, only recently
invented. is a companion piece Of the scales
in the Asssyer's Office of the Treasury, by
which the weight of q hair is accurately
tested.