IMPROVEMENTS IN REGISTERING THERMOMETERS
Year: 1860

page_text: LETTERS PATENT to Robert Henry Capel Wilson, of the Firm of Frank-
ham and Wilson, of No. 12, Wilson Street, Gray's Inn Road, in the
County of Middlesex, Meteorological Instrument Makers, for the Inven-
tion of "IMPROVEMENTS IN REGISTERING THERMOMETERS."
Sealed the 8th March 1861, and dated the 12th September 1860.
PROVISIONAL SPECIFICATION left by the said Robert Henry Capel
Wilson at the Office of the Commissioners of Patents, with his Petition,
on the 12th September 1860.
I, ROBERT HENRY CAPEL WILSON, of the Firm of Frankham and Wilson, of
No. 12, Wilson Street, Gray's Inn Road, in the County of Middlesex, Meteoro-
logical Instrument Makers, do hereby declare the nature of the Invention for
"IMPROVEMENTS IN REGISTERING THERMOMETERS," to be as follows:-
According to my Invention in constructing a maximum and minimum
thermometer, I prefer to use a tube bent into two parallel limbs, each limb
having at its end a bulb or enlargement, which, however, is not new in itself.
Into the bulb at one end of the tube a fluid other than quicksilver, but heavier
than spirit is introduced, and I prefer to use diluted sulphuric acid for the
purpose, though other acids or fluids heavier than spirit may be used, so long
as such fluid does not act prejudicially on quicksilver, or on the tube; this
constitutes the minimum end of the thermometer; beyond this a quantity of
quicksilver is introduced into the tube, and it is preferred that the enlargement
at the other or maximum end of the tube should also be partly filled with the

page_text: same fluid and partly with air. An index or pointer is introduced into the
tube on either side of the quicksilver. The bent tube, thus constructed and
filled, is fixed to a scale, which is arranged in two horizontal lines corresponding
with the two parallel limbs of the tube of the thermometer, and the whole is
arranged in such manner as to be suspended or supported in a horizontal
position, the minimum limb being in one horizontal plane, and the maximum
limb in another horizontal plane parallel to the minimum limb, but it is not
essential that the two limbs or parts of a thermometer should be horizontal.
By thus using dilute acid or fluid heavier than spirit in the bulb of a registering
thermometer, the quicksilver is not liable to divide as when using spirit. It
also admits of a horizontal arrangement of the tube, by which means when the
thermometer is subject to the greater degrees of cold, the equilibrium of the
quicksilver is not liable to be destroyed, as when the quicksilver is in a tube
with two vertical limbs. This Invention is also applicable when making
minimum thermometers.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Henry Capel Wilson in the Great Seal Patent Office
on the 12th March 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
HENRY CAPEL WILSON, of the Firm of Frankham and Wilson, of No. 12,
Wilson Street, Gray's Inn Road, in the County of Middlesex, Meteorological
Instrument Makers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of September, in the year of our
Lord One thousand eight hundred and sixty, in the twenty-fourth year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Robert Henry Capel Wilson, Her special licence that
I, the said Robert Henry Capel Wilson, my executors, administrators, and
assigns, or such others as I, the said Robert Henry Capel Wilson, my
executors, administrators, and assigns, should at any time agree with, and
no others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN REGISTERING
THERMOMETERS," upon the condition, (amongst others) that I, the said Robert
Henry Capel Wilson, my executors or administrators, by an instrument in

page_text: writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Robert Henry Capel Wilson, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
According to my Invention in constructing a maximum and minimum
thermometer, I prefer to use a tube bent into two parallel limbs, each limb
having at its end a bulb or enlargement, which, however, is not new in itself:
Into the bulb at one end of the tube a fluid other than quicksilver, but heavier
than spirit is introduced, and I prefer to use diluted sulphuric acid for the
purpose, though other acids or fluids heavier than spirit may be used, so long
as such fluid does not act prejudicially on quicksilver, or on the tube; this
constitutes the minimum end of the thermometer; beyond this a quantity of
quicksilver is introduced into the tube, and it is preferred that the enlargement
at the other or maximum end of the tube should also be partly filled with the
same fluid as that contained in the other bulb, and partly with air. An index
or pointer is introduced into the tube on either side of the quicksilver. The
bent tube thus constructed and filled is fixed to a scale, which is arranged in
two horizontal lines corresponding with the two parallel limbs of the tube of
the thermometer, and the whole is arranged in such manner as to be suspended
or supported in a horizontal position, the minimum limb being in one
horizontal plane, and the maximum limb in another horizontal plane parallel
to the minimum limb, but it is not essential that the two limbs or parts of a
thermometer should be horizontal. By thus using dilute acid or fluid heavier
than spirit in the bulb of a registering thermometer, the quicksilver is not
liable to divide when the instrument is placed in a horizontal position, as
when using spirit. It also admits of a horizontal arrangement of the tube, by
which means when the thermometer is subject to the greater degrees of cold,
the equilibrium of the quicksilver is not liable to be destroyed, as when the
quicksilver is in a tube with two vertical limbs, and the use of indices without
springs is obtained. This Invention is also applicable when making minimum
thermometers.
Having thus stated the nature of my Invention, I will proceed more fully
to describe the manner of performing the same.

page_text: DESCRIPTION OF THE DRAWING,
which represents a front view of a thermometer constructed according to my
Invention.
a, a, b, b, is a bent tube, having at the two ends hollow bulbs c and d. The
limb a, a, and bulb c, constitute the minimum thermometer. The limb b, b,
and bulb d, constitute the maximum thermometer. . In the bulb c, c, is placed
a fluid considerably heavier than the spirit heretofore used in thermometers,
and such as will not act prejudicially on the quicksilver. I prefer to
employ dilute sulphuric acid, using one part by measure of water, and two
parts concentrated sulphuric acid, but this may be varied, or other fluid heavier
than spirit used in place thereof. In the bulb da like heavy fluid and air is
placed. Intermediate of the two bulbs c and d part of each limb and round
the bend the tube contains quicksilver. In the arrangement shown the
thermometer is suspended horizontally by the eyes f, f, but this may be varied.
e, e, are two pointers interior of the tube, such as have before been introduced
in thermometers.
Having thus described the nature of my Invention, and the manner of
performing the same, I would state that the peculiarity consists in the employ-
ment of dilute acid or other fluid (not acting prejudicially on quicksilver)
heavier than spirit, in combination with quicksilver in the construction of
maximum and minimum thermometers, as herein described.
In witness whereof, I, the said Robert Henry Capel Wilson, have here-
unto set my hand and seal, this Ninth day of March, in the year
of our Lord One thousand eight hundred and sixty-one.