Union County courier. [volume] (Elk Point, Union County, D.T. [S.D.]) 187?-1913, 1892-04-08
MAKING a
Il 10 Done Quickly but with 0rest As-
curacy by Accom pitsbNd WorkerA,

W W oAhS va 49, -
the skilled mechanic, according to the
sort OF Thermometer made. says the
New York Sun. With the extremely
sensitive and infinitely accurate in
struments designed for scientific uses
great are Is taken, and they are kept
in stock for months, sometimes for
years, to be compared and recor1pafed
with instruments that are known to
be trustworthy. But SO much time
cannot be spent vcr the compare
lively cheap thermometers in COM
mon use. and these are made rapidly,
though always carefully. The method
of manufacture has been 50 system
atized within Il few years that the
very cheapest thermometer should
not vary more than a fraction OF a de-
gree from the correct point.
Whether the thermometer is to be
charged with mercury or alcohol;
whether it is to be mounted in a
frame OF wood, pressed tin or brass,
the process is substantially the same.
Mercury Is generally used for scientific
instruments 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 glass-blower on
the premises cuts these tubes tc the
proper lengths and with his gas-jet
aDd blow-pipe makes the bulb on the
low er end. The bulbs are then filed
witt colored alcohol and the I lbes
stand for t%wenty-four hours.
On the following day another work
man holds each bulb in turn over a
gas-jet until the colored fluid bT%its
expansion entirely fills the tube. 1t
then goes back into the hands of the
| glass-blower. lie closes the upper
end and turns the tip backward to
make the little glass hook which will
help keep the tube in place in the
frame.
The tubes now rest until some hun
dreds of them, perhaps thousands, are
ready. Then the process of gauglng
begins There are no marks what
eve Oh the tube, and the first guide
mark to be made is the freezing point,
30 degrees Fahrenheit. This is found
by plnnging the bulbs into melting
snow. No other thermometer is
needed for "A guide, for melting now
gives invariably the exact freezing
point. This is an unfailing test for
any thermometer whose accuracy may
be suspected. But melting snow Is
not always to be had, and a little ma
chine resembling a sausage-grinder Is
brought INTO use. This machine
shaves a block of ice into particles.
which answer the purpose as we'll as
snow.
When the bulbs have been long
enough in the melting snow a work
man takes them one by N from their
icy bath, Selling each one 50 that his
thumb nail marks the exact spot to
which the fluid has fallen. Here he
makes a scarcely perceptible mark
upon the glass with a fine file and
goes on to the next.
The tubes. with the freezing point
marked on each, now 60 into the
hands Of another workman, who
plunges them, bulb down. into a ves
sci filled with water kept constantly
at 81 degrees. A standard Their
mometer attached to the inside OF
this vessel shows that the temper
allure of the water is correct. An
other tiny file scratch is put at 81.
Then IA third workman plunges the
bulbs into another vessel of water
kept constantly at 90 degrees. This
is marked like the others and the
tube is now supplied with these guide
marks, each b degrees from the next.
a small table is then attached tC
each tube. on which its number is
w~ritten-for, owing to unavoidable
variations in the bore of the tube,
each n varies slightly from the
others.
With its individuality thus estab
lished the tube goes into the hand.
OF a maker, who fits its bulb and hoor
into the frame it is to occupy ant
makes slight scratches on the frame
corresponding to the b, 81 and 81
degree marks on the tube. Tn,
frame has Il number corresponding
with the number Of the tube and thu
tube is iald away i'm a rack amid thou
sands.
The frame, whether it be wood, tin
or brass, goes to the gauging-room
where it is laid upon Il steeply slopins
table, exactly in the position marked
for a thermometer of that size. TIL,
81, Ga and SO degree marks must cor
respond with the marks upon tn,
table. If they do not the error il
marking is detected and the frame Il
sent back for correction.
A long, straight bar of wood O
metal extends diagonally across tn,
table from the lower right-hand cor
c to the upper left-hand corner
On the right this works upon a pivot
and on the left it rests in a ratchet
which lets it ascend or descend onl,
n notch at a time. That motel
marks the exact distance Of two de
grees. With the three scratches al
ready made for a basis the marker
could hardly make a mistake in thu
degrees il he tried.
The marks made upon the frame Of
case are all made by hand with ;
geometric pen and India ink il thu
frame is of wood and with steel die.
If it is Of metal. The tube bcarins
the corresponding number is next at
tached to the frame, and the Their
mometer is ready for The market
without further testing. Som,
makers use only two guide marks
but the best makers use three.
In the process of manufacture tn,
ordinary thermometer goes through
the hands of nineteen workmen, hal
of whom are often girls and women
Some of the larger concerns in ant
near New York produce several hun
dred thousand instruments annually
and on every n OF them the pur
chaser may see, il he looks closely
tho tinv scratch on the glass cf 20