AN IMPROVEMENT IN BAROMETERS, GAUGES, AND OTHER ANALOGOUS INSTRUMENTS
Year: 1858

page_text: LETTERS PATENT to Edward John Michael Cetti, of Brook Street, in the
County of Middlesex, Mathematical Instrument Maker, for the Inven-
tion of "AN IMPROVEMENT IN BAROMETERS, GAUGES, AND OTHER ANALOGOUS
INSTRUMENTS."
Sealed the 11th January 1859, and dated the 31st July 1858.
PROVISIONAL SPECIFICATION left by the said Edward John Michael
Cetti at the Office of the Commissioners of Patents, with bis Petition,
on the 31st July 1858.
I, EDWARD JOHN MICHAEL CETTI, of Brook Street, in the County of Middle-
sex, Mathematical Instrument Maker, do hereby declare the nature of the
said Invention for "AN IMPROVEMENT IN BAROMETERS, GAUGES, AND OTHER
ANALOGOUS INSTRUMENTS," to be as follows:-
My Invention of an improvement in barometers, gauges, and other analo-
gous instruments relates to a novel mode of constructing the tube of these
instruments, whereby they are rendered less liable to derangement than here-
tofore, and may be carried or moved about without the risk of being put out
of order so long as the tube is not broken.
In that construction of barometer known as the wheel barometer it has..
been usual, in order to make the instrument portable, to adapt to the glass
tube a metal stop-cock, whereby the mercury may be secured in. the glass
tube, and prevented from moving therein.

page_text: The mode heretofore employed for adapting the metal stop-cock to the
glass tube of wheel barometers consists in inserting the lower end of the
mercury tube into a socket of the metal stop-cock, in which it is secured by
cement or otherwise, as is well known. The tube connected with the mercury
cistern is adapted to a similar socket at the other end of the stop-cock, and is
similarly secured therein. It has been found by experience that the joints
thus made are very liable to leak, and the accuracy of the instrument will
therefore be affected.
Pediment barometers, or that construction usually employed for marine or
mountain baronieters, or for use in mines, are made portable in a different
manner, but in a way that is also open to grave objections, which it is the
object of the present Invention to obviate.
My improvement consists in making the glass tubes of the above or other
analogous instruments with the cistern and stop-cock all in one piece.
By thus making the stop-cock of glass, and forming part of the tube itself,
the necessity of making joints is dispensed with, and the risk of such joints
being defective, and thereby affecting the accuracy of the instrument, is
obviated.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward John Michael Cetti in the Great Seal Patent
Office on the 29th January 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
JOHN MICHAEL CETTI, of Brook Street, in the County of Middlesex, Mathe-
matical Instrument Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirty-first day of July, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year of
Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said. Edward John Michael Cetti, Her special license that I,
the said Edward John Michael Cetti, my executors, administrators, and
assigns, or such others as I, the said Edward John Michael Cetti, 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 "AN IMPROVEMENT IN BAROMETERS,

page_text: GAUGES, AND OTHER ANALOGOUS INSTRUMENTS," upon the condition (amongst
others) that I, the said Edward John Michael Cetti, by an instrument in
writing under my hand and seal, should particularly 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 Edward John Michael Cetti, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
My Invention of "An Improvement in Barometers, Gauges, and other
analogous Instruments" relates to a novel mode of constructing the tube of
these instruments, whereby they are rendered less liable to derangement than
beretofore, and may be carried or moved about without the risk of being put
out of order as long as the tube is not broken.
In that construction of barometer known as the wheel barometer it has
been usual, in order to make the instrument portable, to adapt to the glass
tube a metal stop-cock, whereby the mercury may be secured in the glass
tube, and prevented from moving therein.
The mode heretofore employed for adapting the metal stop-cock to the
glass tube of wheel barometers consists in inserting the lower end of the
mercury tube into a socket of the metal stop-cock, in which it is secured by
cement or otherwise, as is well known. The tube connected with the mercury
cistern is adapted to a similar socket at the other end of the stop-cock; and is
similarly secured therein. It has been found by experience that the joints
thus made are very liable to leak, and the accuracy of the instrument will
therefore be affected.
Pediment barometers or that construction usually employed for marine or
mountain barometers, or for use in mines, are made portable in a different
manner, but in a way that is also open to grave objections, which it is the
object of the present Invention to obviate.
My improvement consists in making the glass tubes of the above or other
analogous instruments with the cistern and stop-cock all in one piece. By
thus constructing the stop-cock of glass, and causing it to form part of the
tube itself, the necessity of making joints is dispensed with, and the risk of
such joints being defective, and thereby affecting the accuracy of the
instrument, is obviated.

page_text: In the accompanying Drawing I have shewn my improvement adapted to
both a wheel and a pediment barometer.
Fig. 1 is a front or edge view; and Fig. 2, a side elevation of the glass
tube of a wheel barometer; Fig: 3 is an edge view, and Fig. 4 a side
elevation of the glass tube of a pediment barometer. a represents the longer
leg of the barometer tube, and 6 the shorter leg, the upper end of which is
open to the action of the atmosphere, and forms the cistern or reservoir for
the mercury; c is the glass cock, which is made in and forms part of the
bent tube a, b, and is provided with a glass spigot d, which is ground to fit.
the transverse hole of the glass cock. The spigot d is screwed at the end,
and is provided with a nut e, whereby it is held securely in its place. At the
other end of the spigot d there is a handle or thumbpiece, whereby it may.
be turned when required.
Having now described my Invention of "An Improvement in Barometers,
Gauges, and other analogous Instruments," and having explained the manner
of carrying the same into effect, I would observe that the same principle of
construction is applicable to water and steam gauges and other analogous
instruments in which a column of mercury is used in glass tubes or vessels to
indicate varying weights or pressure.
In conclusion, I claim, as the Invention secured to me by Letters Patent
as aforesaid, making the glass tubes, cocks, and cisterns of the above-
mentioned and other analogous instruments in one piece, so as to dispense
with the necessity of making joints therein, for the purpose of fitting or
securing the several parts together.
In witness whereof, I, the said Edward John Michael Cetti, have here-
unto set my hand and seal, the Twenty-seventh day of January, in
the year of our Lord One thousand eight hundred and fifty-nine.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
E. CETTI. (L.S.)