The White Pine news. [volume] (Treasure City, Nev.) 1868-1906, 1903-04-02
THERMOMETER MAKING.
How Boiling and Freezing Points Are
Found aud Degrees Marked.

How Boiling and Freezing Points Are
Found aud Degrees Marked.
The making Of a thermometer may
be either "A delicate scientific operation
or one of the simplest tasks OF the
skilled mechanic, according TO the SORT
of thermometer made. With the eX-
tremely sensitive and infinitely aecur-
ate Instruments designed for scientific
uses great care is taken aud they are
kept in stock for months. sometimes
years, to be compared with mstru-
ments that are known to be trust
worthy. But so much time cannot be
spent over the comparatively cheap
thermometer in common use, aud these
are made rapidly, though always care
fully
Mercury IS generally used for seien-
tifle instruments, but most makers pre-
fer alcohol because il is cheaper. The
alcohol is eolored red with aniline dye,
which does not fade. Tie thermom.
eter maker buys his glass tubes In
long strips from the glass factories.
The glass blower on the premises cuts
these tubes to the proper lengths, aud
with his gas jet and blowpipe makes
The bulb on the lower end. The. bulbs
are then filed with colored alcohol and
the tubes stand for twenty-four hours.
on the following day another workman
holds each bulb IN turn over a gas jet
until the colored fluid by It's expansion
entirely fills the tube. 1t then goes
back into the hands of the glass blow
err. lie closes the upper end and turns
the tip backward to make a little hook.
which will help keep the tube in place
in the frame.
fhe tubes rest until some hundreds
Of thcm, perhaps thousands. are ready
Then the process Of gaugng begins
There are no marks on the tube and
the first gulde-mark TO be made Is the
freezing point. 81 degrees Fahrenheit
This is found by plunging the bulb
into melting snow. No other thermom-
eter is needed for a guide, for melting
snow gives invariably the exact freez-
ing point. This is an unfaillng test for
amy thermometer when accuracy may
be suspected Bur melting snow is
not always to be had and n little ma
chine resembling Il sausage grinder Is
brought into use. This machine shayes
a block Of ice into particles, which
answer the purpose ms well as snow.
When the bulbs have been long enough
in the melting snow n workman takes
them one by one from their bath, seiz
ing each so that his thumb nail marks
the exact spot to which the fluid has
fallen. Here he makes a scarcely per
eeptible mark upon the glass with IA
inc 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 the
bulb into a vessel filed with water
kept constantly at 90 degrees This
is marked like the others. and the tube
Is now supplied with these guide
marks, each 81 degrees from the next.
With It's individuality thus establish
ed. The tube goes into the hands Of a
marker. who fits rs bulb and hook
into the frame It is TO occupy and
makes slight scratches on The frame
corresponding 10 the 81 degrees 90
degrees and 06 degrees marks on the
tube
The frame. whether It be wood. tin
or brass goes 10 the gauglng room,
where It is laid upon a steeply sloping
able marked exactly In the position
for n thermometer Of that Size.
\ long, straight bar Of wood or met
Al extends diagonally across the table
from the lower righthand corner 10
the upper lefthaud corner. On tho
right this rests upon pivot and on
The left II rests IN a raehet, which les
II ascend or descend only one notch
at time. Each notch marks the ex-
act distance Of two degrees.-.London
Express.