IMPROVEMENTS IN BAROMETERS
Year: 1881

page_text: LETTERS PATENT to Benjamin Joseph. Barnard Mills, of the Firm of Harris
and Mills, of 23, Southampton Buildings, in the County of Middlesex, Patent
Agent, for an Invention of "IMPROVEMENTS IN BAROMETERS.": A commu-
nication from abroad by Messieurs S. Guichard and Company, of Paris, in the
Republic of France
PROVISIONAL SPECIFICATION left by the said Benjamin Joseph Barnard
Mills at the Office of the Commissioners of Patents on the 9th May
1881.
BENJAMIN JOSEPH BARNARD MILLS, of the Firm of Harris and Mills, of
23, Southampton Buildings, in the County of Middlesex, Patent Agent. "IMPROVE-
MENTS IN BAROMETERS." A communication from abroad by Messieurs S. Guichard
and Company, of Paris, in the Republic of France.
The Invention has for its object the production of a barometer, so arranged as
to give precise indications sufficiently large to be read upon a dial similar to those
of public clocks.
In order the better to explain the Invention, I have represented in the
accompanying Drawings an example of the node in which the same may be
carried into effect.
a is a rectangular frame or box enclosing the mechanism, the vertical sides of
this box are tied together at or near the centre thereof by a shaft b and a
bar c.
The mechanism is composed of two groups of barometric chambers d. These.
chambers are placed in juxta-position and act independently of each other, and can
be arranged in groups of any desired number of chambers.
The end chamber of each group carries a shaft e articulated to a lever f, carrying
at its end a segmental rack g.
Two groups of barometric chambers are preferably employed in order to obtain
sufficient effort to operate the large hand or pointer h, represented by dotted lines

page_text: in the Drawing, and also in order to give greater firmness in the transmission of
the motion.
The lever fis articulated upon a pivot mounted between the bar c and an car
or lug i, which is shown by dotted lines, to permit of the articulation of the shaft e
upon the lever f to be seen.
The segmental rack g carried by the lever f takes into and gives motion to a
pinion, upon the shaft or axis of which is mounted the hand or pointer h.
In order to enable the apparatus to be regulated according to the altitude at
which it is intended to furnish indications, the upper side of the box a is made
moveable upon its joint a¹, a screw m traversing a block n and surrounded by a
spiral spring o causes the said side of the box to rise or fall, and consequently to
regulate the position of the upper group of barometric chambers to set the apparatus
at the proper point.
The number of barometric chambers in each group being variable, barometers can
be constructed on this system, capable of giving indications upon very large dials,
which was impossible with the systems heretofore employed, the power of which
was not sufficient to operate large hands or pointers.
Any other convenient arrangement may be substituted for the means of
adjustment or regulation above described.
The barometric chambers composing the two groups of the mechanism may be
made of any suitable metal; and by making them of similar metal to that employed
for the framing a, the influence of any difference in expansion can be avoided.
It will be evident that the form, dimensions, and arrangement of detail of the
apparatus may be varied to suit different requirements.
For example, several groups of barometric chambers may be placed on each side
of the lever f.
The segmental rack and pinion may also be replaced by any other equivalent
mechanism, such as a bow string and pulley, an endless chain, or other means.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Benjamin Joseph Barnard Mills in the Great Seal Patent Office
on the 8th November 1881.
BENJAMIN JOSEPH BARNARD MILLS, of the Firm of Harris and Mills, of
23, Southampton Buildings, in the County of Middlesex, Patent Agent.” “IM-
PROVEMENTS IN BAROMETERS." A communication from abroad by Messieurs..
S. Guichard and Company, of Paris, in the Republic of France.
The Invention has for its object the production of a barometer, so arranged as to
give precise indications sufficiently large to be read upon a dial similar to those of
public clocks.
In order the better to explain the Invention, I have represented in the
accompanying Drawings an example of the mode in which the same may be
carried into effect.
a is a rectangular frame or box enclosing the mechanism; the vertical sides of
this box are tied together at or near the centre thereof by a shaft b and a
bar c.
The mechanism is composed of two groups of barometric chambers d. These
chambers act independently of each other; they are placed in juxta-position with
each other and soldered, and can be arranged in groups of any desired number of
chambers.
The end chamber of each group carries a shaft e articulated to a lever f carr ing
at its end a segmental rack g.
Two groups of barometric chambers are preferably employed in order to obtain
sufficient effort to operate the large hand or pointer h, represented by dotted lines
in the Drawing, and also in order to give greater firmness in the transmission of
the motion.
The lever fis articulated upon a pivot k mounted between the bar c and an ear
or lug i, which is shown partly by dotted lines, to permit of the articulation of the
shaft e upon the lever fto be seen.
The segmental rack g carried by the lever ftakes into and gives motion to a
pinion, upon the shaft or axis of which is mounted the indicating hand or
pointer h. In order to enable the apparatus to be regulated according to the
altitude at which it is intended to furnish indications, the upper side of the box a
is made moveable upon its joint a¹; a screw m traversing a block n and surrounded
by a spiral spring o causes the said side of the box to rise or fall, and consequently
to regulate the position of the upper group of barometric chambers to set the
apparatus at the proper point.
The number of barometric chambers in each group being variable, barometers
can be constructed on this system capable of giving indications upon very large
dials, which was impossible with the systems heretofore employed, the power of
which was not sufficient to operate large hands or pointers.
Any other convenient arrangement may be substituted for the means of
adjustment or regulation above described.
The barometric chambers composing the two groups of the mechanism may be
made of any suitable metal, and by making these of similar metal to that
employed for the framing a the influence of any difference in expansion can be
avoided.
It will be evident that the form, dimensions, and arrangement of detail of the
apparatus may be varied to suit different requirements. For example, several
groups of barometric chambers may be placed on each side of the lever f.

page_text: The segmental rack and pinion may also be replaced by any other equivalent
mechanism, such as a bow or segment string and pulley, an endless chain, or other
means.
Having thus described the nature of the said Invention, and the mode in which
the same is carried into effect, I would have it understood that what I claim is,―
First. In a barometer giving large indications, the combination of two groups of
barometric chambers & independent of each other, and acting on each side of the
pivot of a lever f, as described and for the purpose specified.
Second. In a barometer giving large indications, the combination of two or
several groups of barometric chambers, and of the lever upon which they act, with
a toothed segment g and a pinion or their equivalent, transmitting to the
indicating hand or pointer the oscillations of the lever, as above described and for
the purpose specified.
Third. In a barometer giving large indications composed of two or several
groups of barometric chambers acting upon a lever which operates the indicating
hand or pointer, the combination with the acting parts of a moveable side a of the
box or other moveable piece with a spring o and a screw m or their equivalent,
substantially as above described and for the purpose specified.
In witness whereof, I, the said. Benjamin Joseph Barnard Mills, have
hereunto set my hand and seal, this Eighth day of November, in the year
of our Lord One thousand eight hundred and eighty one.