The Manitowoc tribune. [volume] (Manitowoc, Wis.) 1866-1878, 1869-02-11
How Thermometers are Made.
From Our Young Folks for Februarv

sWhat is this 2 said Lawrence, pick
| ing up a piece of glass from the floor.
1T looks ike broken thermometer
tube"
1T was blown for one.' said the gaf-
Ter.
::Blown? so small" exclaimed Law
renee. 81 can't find any hole in it. -
1T has hole-or bore. as we call it
of the usual size; but it is 1las. That is
to make very little mercury look to be
a good deal Do you see narrow white
stripe running the length Of the tube?''
Lawrence saw it, and said he had often
observed the stripe in the backs of the
thermometers, but had never learned
what it was for
1t is background to see the mercury
against. Would you like to see such a
tube made? Cone here Watch this
man.
With delight and curiosity Lawrence
watched. The man was gathering a lump
of metal from one of the pots. He blew
it gently and shaped it on "A naryer, fiat
teung it until it rescmbled in form and
size that part of a swordhiit that is
gra<ped by the hand
Inhlttening it" said the caffcr, che
flattened the bubble Of air he had blown
into it. Lawrence looked and could see
the bubble, about as broad as his finger,
extending through the glass. That is to
be the bore of the -thou.h
of itself il is now larger than two or three
thermometer tubes Now they are going
to put on the Stripe
"A boy broug lit lump of melted opaque
white glass on ponty 1t Yves touched
TO the now hardened sword hilt, and
drawn from end to end along the fiat side,
leaving stripe abort as broad as IA lady 5
hnger. The sword-hllt, with the stripe
carefully pressed down and hardened
upon 1t, was now plunged into IA pot Of
melted glass, and thlckly coated, the soft
exterior was rounded on a marver, until
the entire body of glass, enclosing the
stripe and the tattened bore, was in size
and shape a llctle longer and considerably
larger than a banana.
This was now slowly heated to a melt
ing state. Then came forward boy with
u ponty, bearing On its end piece of
glass resembling an inverted conica ink
stand. This hese upright on the ground
the bottom of the inkstand uppermost.
The blowor witt. the melting lump, now
advanced, and held it over the ponty, un-
til the soft mass dropped down and touch
ed the bottom OF the inkstand, to which
1t adhered. The man and the boy held
the lump moment between them then
at word OF command, the boy shoulder
ed his ponty, like very large staff with
very small bundle on the end OF it, and
set out to trayel. As he ran IL one di-
rectlon into u work room, the man backed
Oft in the other, the glowing lump stretch
ing between them, like some miraculous
kind of spruce gum. In minute, they
were seventy or eighty feet apart, with a
cleaning cord of glass, smaller than a
pipe stem, sagging between them. This
was presently lowered, laid out at it's 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, 1T is
| marvellous. 1t Is truly marvellous -
"Of course, said the gaffer, the bore
stretches with the tube, and keeps its
fattened shape. So does the stripes
But what keeps the tube of uniform
size +? Why don't it break?' SAID Law
renee.
The reason is this: As the glass runs
out thin it cools, and stops stretching,
while it continues to draw out the soft
glass from the thicker parts at the ends.
Ii we wish to make a small tube we
stretch it quick, without giving it much
time to cool. To make a large TUBE we
stretch slower. Here is piece of baro-
meter tubing, stretched in the same way;
| SO Is this lot of homeopathic medicine
viais. y The walls were small stack
of hollow glass canes, about five feet In
! length, standing in corner of the work
room, into which we mad followed the
boy. Though, of course" added the
gatfer, TO make them, we don t tatten
| the bore, but only blow it larger.
Then how are vials made out Of these
tubes r.
They are cut into pieces of the right
length, then the bottoms are melted and
closed In by means Of common blow
pipe, such as chemists use.
Lawrence was about to ask q singular
question with regard to the thermometers
when a man came along ard, stopping,
commenced cutting the long tuble inio
uniform lengths OF about five feet, and
packing them together in Il n;.isow, long
box.
These" said the gaifer, che sends
to his shop in Boston for he is "a Their
InoiIictCT LhdkcT, tilcTe Incy are cut up
into tubes OF the right length; an end Of
each one is melted and blown out into IA
bulb. the tube itself serving as very
small blowing ppe. 10 avoid getting
moisture into the bulb, instead oi breath
from the mouth air from q small india
rubber bag is used As the bag is squcez-
ed at one end, the bulb Swelis cut at the
| other -
Then how is the mercury pat in so
small Il hore?' said Lawrence, trying to
find 1t with pin point
The glass Is heated and that expands
the air in it, and expels the greater part
OF 1t. As the air t lat is left oools and
contracts. il is made to suck in the mer-
curry. TO eXpel the rest Of the air, the
mercury Is boiled in the tube.
When there Is enough mercury in the
tube to ill it is high as a degree OF tenn
perature as it Is expected ever TO 90, the
eud is sotteued bent over and closed up
As the mercury cools and contracts. it
leaves a vacuum at the upper end OF the
tube.
GOOD evening, Gen. Grant
said a pleasant-otlice seeker, the other
night Il have not been to see Won Gen