The Ohio Democrat. (Logan, O. [Ohio]) 1886-1906, 1891-04-11
TuE THERMOMETERS.
Something About It's History From ITS
Earliest Inc option.

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Earliest Inc option.
The invention of the thermometer
marks an epoch In science, for It alone
has permitted of obtaining knowledge
Of the laws that govern calorifc phe.
nomena. The first idea of II is perhaps
due TO the celebratedVan Helmont, who
devised an apparatus which, to use his
words, was ito prove that the water
contained in bulb attached TO a hollow
rod rises or descends according TO the
temperature of the surrounding medi-
UNI"
In the seventeenth century, the ne
cessity of an apparatus adapted for
measuring the differences of the tenn
perature was SO greatly felt that Cali
leo, Bacon, Scarpi, Fludd, Borelli and
other scientists devoted themselves in
this direction To researches that were
not always crowned with success. 1t is
not till 1921 that we find a beginning of
the solution in the experiments Of a
Dutchman, Cornelius Van Drebbel.
This physicists thermometer consisted
of tube filed with air, closed at its
upper extremity and dipping at its other
NNlilCh was OlOhD III a DObJlt
containing nitric acid diluted with
water. According as the external tenn
perature rose or fell, the air in the tube
increased or disminished in volume, and
consequently the liquid descended or
rose.
This instrument, called the lcdlenddro
Uitrum Indicating glass; by its inventor,
constituted what has since been called
an air thermometer, but as its lgradua-
ton was based upon no definite princi
pie, it was incapable of furnishing any
comparable reading
Along about 1850 the members Of the
Academia del Cimento, at Florence, in
troduced into the thermometer certain
improvements that gave it nearly the
form that it has to-day; and its princi-
pie was based upon the expansion of
liquids. The tube was filled with col
ored alcohol In order to graduate it,
it was taken to a cellar and the place
was marked where the liquid came to
rest. Then, starting from this, the por-
tions situated above and below the
mark were divided into one hundred
equal parts. As may be seen, 1t was
impossible with such system to con-
struct two instruments that should
agree, Nevertheless, it was the only
apparatus that was made use of for
half century.
Finally, in the latter part of the
seventeenth century, the physicist Re-
naldini, of Pisa, a professor at Padua,
proposed that all thermometers should
take the freezing degree of water as a
fixed point, and, as a second fixed point,
that to which alcohol rises in tube
dipping in melted butter, the interven
ing space to be divided into equal parts.
From this epoch, then, dates the pres
ent thermometer, and the first instru-
ment due to this innovation dates back
to 1901. This was constructed by New
ton, and was the first thermometer Civ
ing comparable readings that had been
devised. The liquid that he adopted
was linseed oil, which is capable of sup
porting higher temperature than alco-
hol without boiling, and his fixed point
of graduation for the upper limit was
the heat of the human body, and for the
lower, the point at which the oil stops
at the moment of it's congelation.
A search soon began to be made for a
thermometrie agent other than oil
(which was too feebly expanded by heat
and which congeals at but a slightly
elevated temperature), and, in 1714, Ga
briel Fahrenheit, of Dantzig, almost
completely solved the problem in the
construction of the thermometer that
now bears his name, This was imme-
diately adopted in Germany and England
(where it is still employed) and was in
troduced into France. But along about
1880, scientists gave preference to the
one that Reaumur had just devised.
Finally, in 1741, Celsius, aprofessor at
Upsal, constructed the instrument called
the centigrade thermometer.
The three last-named instruments are
the ones most commonly used, and differ
only in the graduation of each.-La Sci
ence en- Farnille.