Watertown republican. [volume] (Watertown, Wis.) 1860-1906, 1884-01-02
Thermometers.
TFrom the New York SUM-

"First- class thermometers for fifteen
cents - called out man, who stood IN
the lower part of Broadway with large
basket of thermometers in front of him.
Here is good chance to buy per-
feet register of atmospheric tempera-
ture for the small sum of dime and
half. Step forward gentlemen, and en-
brace your opportunity y
The thermometers were inclosed in
neat iapanned tin cases, and the scales
were silver plated and marked in black.
Some of the tubes held mercury and
some held colored alcohol.
"I cannot comprehend how thermOm-
eters can be manufactured at that price,
thermometer maker said. where can
the profit be? You have no idea of the
great trouble and the amount of time
that it takes to make an accurate Their
mometer. L know that thermometers
can be bought throughout the city any
where from fifteen cents up, and must
say, also, that many of them are good
thermometers. These cheap thermome-
tiers are not manufactured In this city.
They come chiefly from Connecticut,
where there are several large factories,
which turn them out in great numbers.
"Why are accurate thermometers so
costly to make?"
"In the first place, we buy the glass
tubes and test them. According to my
experience, only one out of every six is
fit to put into a thermometer"
How are the tubes tested ?"
"By drawing into them short col
umn of mercury and measuring its
length at different points with pair of
dIviders. It is absolutely necessary
Then the bulb has to be blown and
filled with mercury. The air is driven
out of the tube by heating the mercury
to boiling point, and then putting a tip
of sealing wax on the other end. The
amount of mercury necessary for the
tube is regulated by vapcrizing it off.
Then the open end of the tube is closed
by heating the glass. The next thing
is to make the SCALE
"Must fresh scale be made for each
thermometer ?"
"Certainly. To make the scale it is
necessary to have at least two points on
the Dubbed tube which holds the mer-
curry. The points usually selected are
the freezing point and boiling point of
water. For the former the bulb is sur
rounded by ice, and for the latter it is
placed in boiling water. From these
points the scale is made. Each scale is
stamped out by hand. Afterward the
Dubbed tube is fastened to the scale,
which is on a silver plated strip of brass.
It is then fastened in tin case"
care the fifteen-cent thermometers
made in this way? ?"
"I suppose that they must be, and it
is for this reason that don't see where
the profit comes in"
"I Is there no other way of grading q
thermometer than by putting the bulb
In ice and in boiling water p
"Yes. The points may be obtained
by putting the bulbs in water, the tenn
perature of which is told by a standard
thermometer kept especially for that
purpose That method is often used"
"Ismercury better than colored alcohol
in thermometers?
cit is except where the thermometers
are wanted for measuring extreme cold.
Mercury can be frozen solid, but it is
Impossible to freeze alcohol. Expert
ments have been made which show that
the most intense cold known will only
have the effect of making the alcohol
oily IN its appearance. Mercury with
stands more heat before it boils than
alcohol does, for alcohol boils at lower
temperature than water. The kind of
thermometers which have been speak
ng of are those which are most COM
monty used.