A NEW. MODE OF CONSTRUCTING BAROMETERS AND OTHER PNEUMATIC INSTRUMENTS
Year: 1844

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PIERRE.
ARMAND LE COMTE DE FONTAINEMOREAU, of Skinner's Place, Size Lane, in
the City of London, send greeting."
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her.
Letters Patent under. the Great Seal of Great Britain, bearing: date at West-
minster, the Twenty-seventh day of April, in the seventh year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said Pierre
Armand le Comte de Fontainemoreau, Her especial licence, full power, sole
privilege and authority that I, the said Pierre Armand-le Comte de
Fontainemoreau, my executors, administrators, and assigns, and such others
as I, the said Pierre Armand le Comte de Fontainemoreau, my executors,
administrators, or assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed; and in the Island's
of Guernsey, Jersey, Alderney, Sark, and Man, and also, in all Her said
Majesty's Colonies and Plantations abroad, the Invention of "A NEW. MODE
OF CONSTRUCTING BAROMETERS AND OTHER PNEUMATIC INSTRUMENTS;" communicated
to me by a certain Foreigner residing abroad; in which said Letters Patent
is contained a proviso, that I, the said Pierre Armand le Comte de Fontaine-
moreau, shall cause a particular description of the nature of the said Inven-
tion, and in what manner the same is to be performed, by an instrument in
writing under my hand and seal, to be enrolled in Her said Majesty's High
Court of Chancery within six calendar months next and immediately after

page_text: the date of the said in part recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Pierre Armand le Comte de Fontainemoreau, do hereby declare that the
nature of the said Invention, and the manner in which the same is to be
performed, are fully described and ascertained in and by the following state-
ment thereof, reference being had to the Drawing hereunto annexed, and to
the letters and figures marked thereon, that is to say :-
The "New Mode of Constructing Barometers and other Pneumatic Instru-
ments" consists more espècially in the application of thin sheets or diaphragms
of metals, glass, india rubber, or other flexible air-tight substances, to certain
apparatus employed for measuring the pressure and elasticity of the air and
other fluids, in such manner as to form a kind of elastic cushion or buffer,
susceptible of the slightest variation of the pressure of the atmosphere or fluid
with which it is in contact, and, consequently, indicating the amount of the
same by the greater or less depression of the said yielding substances;
and the Invention consists, generally, in the application of the above prin-
ciple to all those pneumatic instruments in which any reciprocating motion
and oscillation takes place upon a variation in the pressure or weight of the
superincumbent column of the atmosphere, or in the pressure of the liquid in
which it is immersed, or in the elasticity of a gascious body, and which instru-
ments, are commonly called barometers and manometers, &c.
I will now, proceed to describe the Drawing appended hereto, explaining in
the course of the description the working action of the apparatus, which is
therein fully delineated.
Figure 1 is a diametrical section of the barometer, Figure 2 being an
horizontal view of the same with the dial plate M taken off, in order to shew
the arrangement of the Sheet B and the cup G. The instrument is constructed
of brass, or any other suitable material impervious to air. The lower part
A, A; is a hollow box stoutly made, and strengthened by radial brackets X, X,
soldered internally to insure rigidity in A. A. This box is covered in an air-
tight manner by a sheet or diaphragm B, B, of metal, glass, &c., very thin,
that it may be the more flexible, and also corrugated circularly so as to enable
it to be depressed or elevated to the greatest extent requisite without rupture:
Underneath this diaphragm are the flat annular disks E; E, E, made up of
segments, or an entire plate, which serve as caps to a number of spiral springs,
for the purpose of supporting it against the atmospheric pressure. The lower
ends of these springs, six of which, C, C, C, C, C, C, may be seen in the
Drawing, are inserted in the cavities cut for them in the false bottom

page_text: D, D, D, D, D. They communicate their pressure to the disks E, E, E, which
diffuse it equally to all parts of the delicate diaphragm.
.
And I would here remark that I do not confine myself to the spiral form;
since I can use steel plates folded in a zigzag manner in lieu thereof. In the
centre of the thin diaphragm B, B, a round hole is cut, and its edges soldered to.
the lips of a small capsulė or cylindrical cup G, which projects into the interior
of the hollow box A, A, sufficient space being allowed between G and D to per-
mit it to be depressed to its greatest required deflection. In the bottom of the
box A, A, and immediately under the cup G, there is a small aperture Z for the
purpose of exhausting the air from the box A, A. This is accomplished in
the following manner :-A little solder is spread round the hole, and a flat-
headed peg inserted therein, sufficiently open to permit the passage of the air.
The diaphragm B, B, with the springs C, C, C, C, C, C, is compressed to its
proper position by means of a board and a press, and is then soldered or
cemented to the box, A, A, being retained in its place by clamps embracing
the board and bottom of the instrument, which in this state is to be placed.
under an air-pump receiver, to which has been previously fitted an air-tight
stuffing.box, through which passes a smooth rod capable of moving.freely
therein. The inner extremity of this rod bears a soldering iron, which must
be heated before commencing to exhaust. This done, all is ready for the
operation of the air pump; and when the vacuum is obtained, both in the
instrument and in the receiver, since they are in communication by the hole z,.
the hot iron must be pressed down upon the peg at Z, and its heat will cause:
the solder to melt around the peg, thereby making a complete and permanent!
joint. The peculiar adaptation. of this barometer to its intended object will,
before I proceed further, be clearly seen. The pressure of the atmosphere.
being removed from the under surface of the thin diaphragm, the weight of
the atmosphere on the upper 'surface will slightly depress the diaphragm; but
this weight is variable according to the state of the weather, consequently, the
amount of depression will be greater or less, in proportion to its variation;
therefore all that is required to complete the instrument is simply to provide
mechanism for accurately measuring this.depression, and exhibiting its amount
on a dial, or other ordinary scale. The contrivance which I have adopted for
this purpose is very simple. In the before-mentioned cup G is placed a small
nut H, with an internal. screw thread. This nut is suspended upon a kind of
universal joint, which will be better understood by a reference to Figure 2.
The nut H, as there seen; is not directly attached to the cup G, but is balanced'
and plays freely on two pivots projecting from a ring, which again is balanced
on two other pivots at right angles to the former ones, and connecting the

page_text: whole with the cup G. This arrangement allows for any accidental deviation
from precision which may occur in fitting together the several parts. A
vertical screw K works in the nut H, or rather is worked by it, for when the
cup G is depressed the nut H catches the thread of, the spindle K, and causes
it to turn round; when the cup G is elevated the spindle naturally turns in the
reverse direction. The upper end of the spindle K passes through the dial
plate M, and carries the index L, which exhibits its variations upon a scale
graduated in inches, or any other convenient standard. And here I would
again observe, that I do not limit myself to the above arrangement, since I can
employ for the same purpose a rack and pinion, or a chain and pulley, with
two bevil wheels (see Figure 6, in which the rack and pinion may be replaced
by a chain and pulley, or a simple lever, the dial plate being placed at right
angles to the diaphragm. The influence of heat and cold in expanding and
contracting metal would, however, disturb the regularity of its action, and the
faithfulness of its indications, if not corrected by some means. When the
increase of temperature of the thin diaphragm causes it to rise, it indicates
erroneously a light state of the atmosphere. This error is counteracted by a
regulating plate O, made of two strips of different metals, brass and steel for
example; the upper one, expanding less than the other, is fixed at Q, Q, Q, Q,
a small piece being left between it and the dial M. One end of this plate
projects as far as the centre of the diaphragm, where a small hole is bored for
the spindle K to pass through. Upon this spindle a collar is fastened,
immediately under and abutting against the plate O, which collar in addition
is provided with a coil spring N, in order to keep it gently in contact with the
said plate, and therefore steady in the nut H. When from expansion by
heat the cup G is elevated, the same temperature also acts upon the plate O,
which, on account of the unequal expansion of the two. metals of which it is
composed, curves upwards to a degree proportional to the heat, and equal to
the height which the cup G has risen at the same moment. This permits the
spindle to rise higher instead of being turned, as would be the case if it were
held down whilst the cup rose. When the apparatus is under the effects of
cold the mechanism will naturally act in the reverse manner, thus constantly
compensating for all foreign influences. The proportion of this compensation
may be lessened or increased by slipping the wedge P nearer to or further
from the spindle K, the screws Q; Q, Q, being placed so as to hold it firmly
in the position required. This approaching or receding of the piece P shortens
or lengthens the play of the regulating plate O, and thus varies the amount of
its deflexions; and when the proper position is once obtained, it must be
permanently fixed there. To graduate the instrument I place it in a bell,

page_text: plunged mouth downwards in a liquid, in the same manner as á gasometer
This vessel is furnished with a manometer, and I vary the pressure by raising
and lowering it, noting at the same time the arcs which the index L describes
upon the dial M, in consequence of the said variations. It will be seen that
in the application of my principle to various useful purposes, any elastic,
and at the same time air-tight diaphragm, may be used, and also that it does
not require any invariable form of apparatus for the successful operation of
the said principle. In exemplification of this I subjoin some modifications of
the above arrangement. These are shewn in Figures 3, 4, 5, and 6. At
Figure 8, in lieu of the corrugated diaphragm B, B, I have substituted one of
copper, a, a, in shape like an annular trough, pierced with radial slots, as will
be observed in the enlarged segment exhibited at Figure 4. This annulus is
coated with a lamina of caoutchouc, and the outer edge is cemented to the box
A, A, the inner edge being attached to the cup G, which, with the rest of the
mechanism, is similar to that of Figure 1, and for the same purpose. Figure 5
represents two plates connected and entirely enveloped by a coating of caout-
chouc, or other supple material. The cylindrical tube of caoutchouc a, a, is
kept distended by an internal spiral coil of wire b, b. The lower plate is fixed
to the bottom of the box A, A, and the upper one carries the cup G, in which
is seen a nut c, with a slightly conical screw thread; for the purpose of receiving
a tightening screw f, which last supports the universal joint of the nut H, as
above described. The air is exhausted through the india-rubber pipe C,
which is strengthened by an internal lead tube coated with wax. When the
vacuum is obtained the pipe C must be pinched, and the projecting portion
cut off, and the place finally sealed with caoutchouc. Figure 6 represents two
plates a, a, similar to the above, connected by a deeply corrugated tube of
metal, glass, or other suitable material. The cup G carries a rack to work
into a pinion above which last communicates its motion by means of two
bevel wheels fixed to the dial to the index L, or if the axis of the tube
m, m, be placed (as shewn in Figure 7) parallel to the dial, the pinion may be
fixed upon the axis of the index L, and the bevel wheel dispensed with. This
mechanism may also be applied to the other modifications of my apparatus.
If the flat projections of the tube m, m, be thin and large, I give strength by
stamping each of them with radial corrugations. In all these forms, if the
diaphragms be not alone sufficiently strong, springs must be employed either
internally or externally between the projecting portions of the upper and
lower plates (as at a, b, Figure 6), or, instead of springs, the air may be
left in the box A, A, but in this case greater play must be given to the
bimetallic regulator, in order to compensate for the great expansion of atmo-
spheric air. The principle, as above exemplified, can also be applied to the

page_text: construction of manometers for measuring the pressure or elastic force of gases
or steam. An arrangement for this purpose. is seen in Figure 8. A. is a
hollow column communicating by its base with the boiler or reservoir of the
fluid to be measured. The top of this column is covered in steam-tight by
the cover b, b, in the centre of which is attached the corrugated tube c, c.
The bottom X of this tube, according as it is more or less compressed by the
steam, raises the standard d, which abuts against the spring e, e. This standard
is forked, as shewn in the side view, Figure 9, and between the two, branches
is suspended on an universal. joint, a nut H, which, in rising or falling,' turns
the spindle screw K. This spindle carries at its upper extremity a bevel
wheel m, which, by communicating with four other bevel wheels, transmits the
indications through their axis n, n, and the indexes L, L, upon the four faces
of the box G.. I can also employ as a manometer the arrangement repre-
sented for the barometer, with this difference, that the springs must be placed
between the flexible diaphragm B, B, and the dial M, the steam or gas being
introduced-into the interior of the box, A, A.. It is obvious that the arrange-
ments herein-before described may be applied measuring the pressure of liquids,
at different depths.
=
And having now described the several purposes in which the principle may
be rendered useful, I repeat that I do not confine myself to the exact details
herein described, but that I claim as of the Invention the application of
flexible air-tight diaphragms of any material sufficiently elastic, and of any
form which will produce the above results, that is to say, to measure the
pressure of fluids, gases, &c., by the deflexions of the said diaphragms, as
above described. And such the Invention being, to the best of my knowledge
and belief, entirely new. and never before used within that part of Her said
Majesty's United Kingdom of Great Britain and Ireland called England, Her
said Dominion of Wales, and Town of Berwick-upon-Tweed, and in the
Islands of Guernsey, Jersey, Alderney, Sark, and Man, and also in all Her
said Majesty's Colonies and Plantations abroad, I do hereby declare this to be
my Specification of the same, and that I do verily believe that this my Speci-
fication doth comply in all respects, fully and without reserve or disguise, with
the proviso in the said herein-before in part recited Letters Patent contained;
wherefore I hereby claim to maintain exclusive right and privilege to the said
Invention.
In witness whereof, I, the said Pierre Armand le Comte de. Fontaine-
moreau, have hereunto set my hand and seal, this Twenty-sixth day of
October, in the year of our Lord One thousand eight hundred, and
forty-four.
P. DE (L.s.) FONTAINEMOREAU.

page_text: AND BE IT REMEMBERED, that on the same Twenty-sixth day of
October, in the year above mentioned, the aforesaid Pierre Armand le
Comte de Fontainemoreau came before our Lady the Queen in Her Chan-
cery, and acknowledged the Specification aforesaid, and all and every thing
therein contained, in form above written. And also the Specification afore-
said was stamped according to the tenor of the Statute in that case made.
and provided.
Inrolled the same Twenty-sixth day of October, in the year above.
written.