The Princeton union. [volume] (Princeton, Minn.) 1876-1976, 1881-08-25
ABOUT THERMOMETERS
Seasoned and Unseasoned Glass and Tinted
Tubes-Minute Graduation.

Seasoned and UnseaSOned Glass and Tinted
Tubes-Minute Graduation.
From the New York Sun.
The manufacture Of thermometers in
this country has quadrupled in the past.
thirty years, and the price Of the cheapest
thermometer has gone down fhom a dollar
to fifteen cents. Talking with Mr.. John
Tagliabue recently, we learned some Curl
GUS facts about thermometers.
The newest thing about them, said Mr..
Tagliabue, is the establishment of a bureau
at Yale college for the testing and vertical
ton of thermometers. It has been known
for some time that q process of molecular
contraction goes on in glass for about two
years after its manufacture. If you a k a
new piece of glass tubing and make a Their
mometer of it, at the end of two years your
graduation marks will be wrong. The
shrinkaee of the glass will make the mer-
curry rise"
"Has this contraction been measured?"
Eyes, by Regnault, a French physicist,
who observed that the greatest part of the
@How do you allow for this in manufac-
turing?"
"For the most delicate work we use glass
tubing that has been laid aside and sea
soned, as we call it, a couple of years. For
other work we sometimes graduate the Their
mometer fve-tenths of a degree too high.
By the time the thermometer is sold to the
retail purchaser it will be right. For ordin-
airy purposes the variation is imperceptible,
and Of no account"
How about c%oloring the tubing to make
the mercury more plainly visible?"
aThat has been tried recently, and found
to be of no practical value where the color
ing is dlstiRct, red, for instance. As a mat
ter of fact, the tubing of the thermometers
has for forty years been tinted with white
at the back. That makes the mercury which
is black, show the most perfect contrast.
I know Of no way of coloring mercury, but
in spirit thermometers the fluid can be tint
ed with various colors.
What practical difference is there be-
tween a spirit anda mercury thermometer"
The mercury is the more expensive and
and the only available substance for deli
cate work. Spirits will show the changes
of temperature in time, but the spirit is not
as sensitive as the mercury, and takes longer
to expand. If you take a spirit thermome-
ter fsom a temperature of twenty degrees
into 1 temperature of seventy degrees it
will not mark seventy degrees IN less than
an hour. A mercurial thermometer would
show it in ten minutes. Therefore a spirit
thermometer would not do for a Turkish
bath or sick room"
"Where is the glass tubing of which ther-
mometers are manufactured produced?"
"Thirty years ago there we've three glass
houses in and near New York. Now we
have to go 800 miles for our glass. The
very best tubing for thermometers is made
in England, because the glass is much more
clear and brilliant. But we make as good
instruments in this country as anywhere"
"What is the cost Of the best thermome-
teri"
The mounting may cost what you please,
made was for Engineer Emory, of the
actually graduated to fftieths Of a degree,
and you can read between the Zines the
hundreth part Of a degree. There are
thermometers made for 50 apiece that are
graduated to read tenths of a degree. What
are called the body thermometers, or clin-
ical thermometers, are made very nicely of
glass We call seasoned for want Of a bet
ter name. They must be graduated with
great accuracy, and you can read eighths
and tenths Of a degree easily"
why did the glass houses move awav?"
That has always been a puzzle to me.
The Brooklyn glass was formerly as goou
as any in the world. But they. broke IN
their establishment and moved to Corning.
because production was cheaper there. Now
the English tube is fifty per cent. better
for the best work"
What country makes most thern.ome-
ters2"
formerly Italy Gid, but Of late years
England and other countries have come in.