The Fremont weekly journal. [volume] (Fremont, Sandusky County, Ohio) 1867-1877, 1869-02-05

How ThermOmeters are made.
'eWhat is this 2" said Lawrence, pick
ing up piece of glass from TIM floor.
at looks like a broken thermometer
tube.p
sIf was blown for one, said the gaf-
fer.
"Blownl-so small ~ exclaimed Law
renee. 81 can't find any hole in il"
at has a hole-or bore, as we call It
-Of the usual size; but it is fat. That
is 10 make a very little mercury look 10
be good deal Do you see narrow
white strip running the length Of the
tubes"
Lawrence saw It, and said he had
often observed the stripe in the backs
Of thermometers, but had never learned
what Il was for.
at Is a background to see the mur-
curry against Would you like to see
such tube madel Come here. Watch
this man."
With delight and curiosity Lawrence
watched. The man was gathering a
lump Of melted glass from one Of the pots.
He blew it gently; and shaped it on a
marvel, hattening it until it resembled
in form and size that part of a sword
hilt that is grasped by the hand.
ON hattening It, said the CATER, che
hattened the bubble of air he had blown
into il" Lawrance looked, and could
see the bubble about as broad as his
finger, extending through the glass"
'That is TO be the bore ofthe thermome-
ter-though of itself it is now larger
than two or thermometer tubes. Now
they are going 70 pat on the stripes"
A boy brought a lump of melted,
Opaque, white glass on a ponty. It was
touched to the now hardened sword-hilt,
and drawn from end TO end along the
fiat side, leaving a stripe about as broad
as slady's finger. The sword hiIt with
the stripe carefully pressed down and
hardened upon it. was now plunged
into a plot Of melted glass, and thickly
coated; the soft exterior was rounded
on a marker, until the entire body of
glass, enclosing the strips and the fiat
tened bore, was in size and shape a
little longer and considerably larger
than banana.
This was now slowly heated to mel
ting state. Then came forward a boy
with pOnty bearing on its end a piece
Of glass resembling an inverted conical
inkstand. This he set upright on the
ground, the bottom of the inkstand up
permost. The blower, with the melt
ing lump, now advanced, and held it
over the ponty, until the soft mass drop
psd down and touched the bottom Of
the inkstand, to which it adhered. The
man and the boy held the lump a mo
ment between them; then, at a word of
cammand, the boy shouldeFed his bon
", ike 3 very large staff with very
small bundle on the end of it. and set
on to travel. As he ran in one direc-
tion, into a working room, the man
backed off in the other, the glowing
lump stretching between them like
some miraculous kind of spruce gum.
10 a minute they were seventy or eighty
feet apart, with q cleaning cord Of
glass, smaller than a pipe-stem, sagging
between them. This was presently
lowered, laid out at its full length upon
the ground, and broken from what was
left of the lump at the ends.
Even the doctor, who had hitherto
said little, now expressed his astonish-
ment and admiration, exclaiming, SIT
Is marvellous ! it is truly marvellous" !"
OF course, said the gafer, the bore
stretches with the tube, and keeps its
Aattened shape. So does the stripe
But what keeps the tube of uniform
Sizei Why don't it break 2 said Law
renee,
The reason is this: As the glass
runs out thin, it cools, and stop stretch
inr, while it continues to draw out the
soft glass from the thicker parts at the
ends. If we wish to make small tube,
we stretch it quick, without giving it
much time to cool. To make large
tube, We stretch slower. Here is piece
Of barometer tubing, stretched in the
same way SO is this lot of homeopathic
medicine walls The vials were a small
stack of hollow glass canes, about five
feet in length, standing in a corner of
the work room, into which the visitors
had followed the boy. Thouh, of
course added the gaffer, TO make them
we don't ilatten the bore, but only blow
it larger
Then how are vials made out of these
tubesF
They are cut into pieces of the right
length, then the bottoms are melted and
closed in by means of a common blow
pipe, such as chemists use.'
Lawrence was about to ask a similar
question with regard to the thermome-
ters, when a man came along and,
STOPPING, commenced cutting the long
tube into uniform lengths of about five
feet and packing them together into
narrow, long box.
a These said the gafsr, 'he sends to
his shop in Boston-for be is a ther-
mometer maker; there they are cut in
to tubes of the right length; an end of
each one is melted and blown out into
a bulb-the tube itself serving as a
very small blowing pipe. To avoid
getting moisture into the bulb, instead
Of breathing from the mouth, sir from
a smaIl india rubber bag is used. As
the bag is squeezed at one end, the bulb
sWells at the other.
Then how is the mercury put in so
small bore 2 said Lawrence, trying to
find it with pin point
The glass is heated, aud that ex-
pands the air in It, aud expels the
greater part of it As the air that is
left cools and contracts, it is make to
suck ia the mercury. To expel the
reat of the sir, the mercury is boiled in
the tube. When there is enough mer-
cury in the tube to fill It, at as high a
degree Of temperature as II is expected
ever 10 find, the end, is softened, bent
over and closed up. As the mercury
cools and contracts, it leaves a vacuum
at the upper end Of the tube. - Young
Folks, February.