The sun. [volume] (New York [N.Y.]) 1833-1916, 1892-02-14
NAKlNG A THERMOMETER.
II IL Done Quiekly. but with Great a ecurscy.
by Nineteen PERSON..

by Nineteen Persons.
The making OF thermometer may DO
either delicate scientific operation. or one OF
the sim plest tasks Of the skilled mechanic. ac-
cording to the sort Of thermometer made.
With the extremely 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 bo
compared and recompared with instruments
that arc known to bo trustworthy. But SO
much time cannot be spent over the compare
lively cheap thermometers in common use.
and these are made rapidly though always
carefully. The method OF manufacture has
been so systematized within few years that
the very cheapest thermometer should not
vary more than fraction OF degree from the
correct point.
Whether the Thermometer Is to be charged
with mercury or alcohol: whether it Is to DO
mounted In frame Of wood. pressed tin. or
brass. the process Is substantially the same.
struments. but most makers, prefer alcohol.
because 1t is cheaper The alcohol is colored
The M thernameter ri maker Buys Il" his glass
tubes in long strips from the glass factories.
The glassblower on the premises cuts these
Jet and blowppe makes the bulb on the lower
end, The bulbs are then filled with colorel
On the following day another workman holds
each bulb in turn over a gas jet until the the col.
9rSd hqd by Its pans nto entirely ms TIE
turns the tip backward to make TIE little glass
hook which will help Keep the tube In place in
4, The tubes now rest until some hundreds Of
is tfs rSssnS n9P
plnnging the bulbs into, melting snow. No
other thermometer is needed for a guide. for
ing point. This IS AN unienx tcs t' Tor s any
posted. But melting snow is not always to BE-
Grinder H Is breus1t into ase This ,naeSins
shaves a block OF lee into particles. which
Wien the bulbs have been long enough In
tho metins snown workman takes them one
msrk se tI1
which the fluid has fallen. Here he makea
scarcely perceptibe mark upon tho glass with
The tubes. with the freezing point marked
on each. nov go into the hands Of another
a vessel filled with water kept constantly at IA
TO the inside Of this vessel shows that the
tiny iile scrateh is put at 81. ~
Then a third workman plunges the bulbs
at Ot;. This is marked like the others. and tic
tube is now supplied with these guido marks
eacn tS degrees from tne next. \ SinIll tab Is
then attached to each tube. on WHICH its num-
her Is written-for. owing to unavoidab BILE vari-
atoms in the bore OF the tube each one varies
slightly from the others.
tube goes into the han ds OF n marker.who fits its
bulb and hook into tho frame it is to occupy.
ana makes slight scratches on the frame. cor
responding TO the 81. t4.andH B degree marks on
the tube. The frame has u number correspond
ing with the number Of the tube. and the
tube il laid away in rack amid thousands.
The frame. whether it be wood tin. or brass.
goes to the Igauginc room. where. 1t is laid upon
marked for "a thermometer Of that size. Tho
~. ~. and ~ degree marks must correspond
with the marks uron the table. II they do not
frame is sent back Tor correction.
A long. straight bar OF wood or metal en-
tends di9gonally across the table from the
corner. On the right this works upon II pivot.
and on tho left 1t rests in q ratchet. which lots
i ascend or descend only one notch ut n time.
That notch marks tho exact distance Of two
made for basis tho marker could hardly
make mistake in the degrees il he tried.
THE ma rEs made ,inon the frame or caso arc
| oil made by hand with q geometric pen and
steel dos IL It Is Of metal. The tube bearng
| tho corresponding number IL next attached to
| the frame. and the Thermometer Is ready for
| the, market without further testing. Somo
best makers lsc three.
| In The process OF manufacture the ordinary
thermometer COOS through the hands. OF nine
| and women. Some OF the larger concerns in
and near, New York produce several hundred
| Thousand instruments annually and on every
| one Q. them the purchaser may sec. i he looks
closely. the tiny flo scratch on the glass at 81.
! o. and ny degree marEs-or somewhere near
| them. as different makers use different points.