Nebraska advertiser. [volume] (Brownville, Nemaha County, N.T. [Neb.]) 1856-1882, 1869-02-18
How Thermometers arem made.

How Thermometers are made.
"What is this?'i said Lawrence pick
ing up a peace of glass from the floor
at looks like a broken thermometer
tube"
at was blown for one" said the
gaffer.
"BlOwn?-so small!' exclaimed Law
renee. II can't find any hole in itn
at has a hOle-Or bore, as we call
of the usual size; but it is fiat. That
is to make very little mercury look
to be a good deal. Do you see narrow
white strip running the length of the
tube?n
Lawrence saw it, and said he had
often Obsesved the stripe in the backs
OfthermOmeters, but had never learned
what it was for.
at is the background to see the
mercury against. Would you like to
see such a tube made? Come here.
Watch this man.
With delightand curiosity Lawrence
watched. The man was gathering a
lump of metal from one Ofthe pots. He
blew it gently, and shaped it on a mar
yer, flatening it until it resembled in
form and size that part of asword hilt
that is grasped by the hand.
SIN flatening it, " said the gaffer she
fiatened the bubble of air he had blown
into it." Lawrence looked and could
see the bubble, about as broad as his
finger through the glass. THAT is to
be the bore of the thermOmeter-tho
of itselfit is now larger than two or
three thermometer tubes. Now they
are going to put on the stripe"
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 fat side, leaving q stripe
about as broad as a lady's finger. The
swOFd-hilt, with the stripe carefully
pressed down and hardined upon it,
was now plunged into pot Of melted
glass, and thiczly coated the soft ex-
terror was rounded on a marveT, until
the entire body Of glass, enclosing the
stripe and the fattened bore was in
size and shape a little longer and con-
siderabIy larger than a banana
This was now slowly heated to q
melting state. Then came forward a
boy with pOnty bearing on its end a
piece of glass resembling an inverted
cOnical ink-stand. This he set on
the ground, the bottom Of the inkstand
luppermOst.
The blower, with the melting lump,
now advanced, and held it over the
DOnty, until thesOft mass drOped down
and touched the bottom Of the inkstand
to which it adhered. The man and
the boy held the lump between them q
moment; then at a word of command,
I the bOv ehouldnrod his nor,f,y Iffro q
very large staff with a very small
bundle on the end Of it'and set out to
/ travel. AS he ran in one direction
into work room, the man backed of
in the other, the glowing lump streeh-
| ing between them like some miraculous
kind Of spruce gum. In o 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 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, exelaiming, Ell
is marvellous! it is truly marvellous
"Of course, said the gaffer, ''ths
bore stretches with the tube and keep:
| its flatened shape. So does the stripe.
"But what keeps the tube of uni
form size? Why don't il break ?" saiC
/ Lawrence.
i stThe reason is this. As the glas
Funs0ut thin, it cOOls, and stops stretch
/ ing while it continues to draw out tn,
glass from the thicker parts at the ends