River Falls journal. [volume] (River Falls, Pierce County, Wis.) 1872-2019, 1893-03-09
ABOUT THERMOMETERS.
Everybody Wants One Nowadays and Nov
wa Tell How They Are Made

we Tell How They Are Made.
The making of thermometer NAV be
either delicate scientific operation, or
one of the simplest tasks of the skilled
mechanic. according TO the sort of
Thermometer you want. With the ex.
tremeiy sensitive and infinitely accurate
instruments designed for scientific uses
great care is taken, and they are kept
in stock for months, sometimes for
years. TO be compared and recompared
with instruments that are known 10 oe
Trustworthy.
But so much time can not be spent
over the comparatively cheap Their
mometers in common use. These are
made rapidly, though always carefully.
The method of manufacture has been
SO systematized within recent years
that the very cheapest Thermometer
should not vary more than the fraction
of degree from the correct point.
Whether the thermometer is to be
charged with mercury or alcohol;
whether it is to be mounted in frame
of wood, pressed tin or brass, the proc
ess is substantially the same. Mercury
is generally used for scientific instru-
ments, but most makers prefer alcohol
because it is cheaper. The alcohol is
colored red with an aniline dye which
does not fade.
The thermometer maker buys his
glass tubes In long strips from the glass
factories. The glassblower cuts these
tubes to the proper lengths, and with
his gas jet and blowpipe makes the
built on the lower end. The bulbs are
then filed with colored alcohol and the
tubes stand for twenty-four hours.
Tn the following day another work.
man holds each bulb in turn
over the gas jet until the coll
ored fluid by its expansion fills
the tube. 1t is then taken back TO the
glass-blower. lie closes the upper end
and turns the top backward to make
the little glass hook which will help
keep the tube in place in the frame.
The tubes now rest until a great
number of them are ready. Then the
process of gauging begins. There are
no marks whatever on the tube, and
the first guide mark TO be made is the
freezing mark.
This is formed by plunging the bulbs
into melting snow. No other Their
mometer is needed for a guide, for
melting snow gives invariably the exact
freezing point. This is an unfailing
test for any thermometer whose ac-
curacy may be doubted. Melting snow
is not always to be had, and little
machine resembling a sausage grinder
is brought into use. This machine
shaves "a block of ice into particles.
which answers the purpose as well as
snow.
When the bulbs have been long
enough in the melting snow, work
man takes them one by one from their
icy bath, seizing each one so that his
thumb nail marks the exact spot to
which the fluid has fallen. Here he
makes a scarcely perceptible mark up
on the glass with fine file and goes on
to the next.
The tubes with the freezing point
marked on each now go into the hands
of another workman, who plunges
them, bulb down, into vessel filled
with water kept constantly at sixty
four degrees. A standard thermome-
ter attached to the inside of this yes
sci shows thai the temperature of the
water is correct. Another tiny file
scratch Is made at sixty-four
A third time the bulb is showed into
water kept constantly at ninety-six.
which, like the others, is marked. A
tab is affixed to each tube. 1t is given
over to the marker, who fits the bulb
and hook into a frame, and makes
slight scratches, corresponding to the
thirty-two. sixty-four and ninety-six
marks. IL is next given over to a
workman, who cuts the degree marks.
Altogether, it takes nineteen work.
people to make thermometer. Nine
are females. Any time you have time
you could not spend half day more
pleasantly than looking at the making
of thermometer. Y. News.