BAROMETERS
Year: 1856

page_text: LETTERS PATENT to Henry Mapple, of Childs Hill, County of Middlesex,
Parish of Hendon, Electric Engineer, for the 'Invention of "BAROMETERS."
Sealed the 21st October 1856, and dated the 1st May 1856.
PROVISIONAL SPECIFICATION left by the said Henry Mapple at the
Office of the Commissioners of Patents, with his Petition, on the
1st May 1856.
I, HENRY MAPPLE,. of Childs Hill, in the County of Middlesex,-Parish of
Hendon, Electric Engineer, do hereby declare the nature of the said. Invention.
for BAROMETERS, to be as follows:-
First, I take a tube or tubes like those used in barometers, I then fix this
tube or tubes in a frame, or they can be made without a frame; I then fill
the tubes with quicksilver, as is usually done; I then ballance the whole upon
a point or pivot, or knife edge, or suspend the said tube or tubes by a silken
cord or other flexible material. By these means I insure a very delicate
action, the least change in the atmosphere being shown by a pointer moveing
in front of an index. I do not confine myself to tubes of quicksilver... I wish
to claim the metheod of supporting or suspending, as above described, when
applied to aney, description of barometers.
Second, to compensate aney change of air or expansion of metal, I fix a
thermometer or metal compensation to the barometer, but this compensation is
not required in all cases.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Mapple in the Great Seal Patent Office on the
31st October 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
MAPPLE, of Childs Hill, Hendon, Middlesex, Electric Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of May, in the year of our Lord One
thousand eight hundred and fifty-six, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Henry Mapple, Her special licence that I, the said Henry Mapple, my
executors, administrators, and assigns, or such others as I, the said Henry
Mapple, 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 "BAROMETERS," upon the condition
(amongst others that the said Henry Mapple, 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 Henry Mapple, 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 (that is to say):-
This Invention relates to an improved mode of constructing barometers and
similar instruments, for shewing rapidly and with certainty the changes of the
atmosphere or other fluids, and consists chiefly in suspending, supporting, or
balancing the instrument on a point or points, or pivot or pivots, or a knife
or other suitable formed edge, or suspending it by a flexible material, as a
silken or other cord, a fine flexible steel spring or any other suitable material,
which allows the instrument to vibrate or oscillate freely; and a pointer or
hand, being fixed to the instrument, and moving in front of an index or dial,
or a segment of a circle, may be fixed to the instrument to move before a fixed
hand or pointer properly divided, shows by its motion the most minute change
in the atmosphere.
A reference to my Sheet of Drawings, which I shall now describe, will better

page_text: explain the construction of my improved instruments. Many modifications may,
be made in their arrangement and construction, and some of them may be
used as a fixed instrument, and will act without suspending or balancing.
(The same letters apply to the same parts in the various Figures).
In Figure 1 of my Drawing a front elevation of one arrangement of my
improved barometer is shewn. Figures 2 and 3 represent an end and front.
elevation of the same to an enlarged scale, and Figure 5 a plan of same.
a, a, is a glass tube, charged with mercury or other fluid in the usual way,
and when placed in position, at an angle, having a vacuum in the upper end of
the tube. The tube is fastened to a framework c by two strips of thin metal.
s, s, or in any other suitable way attached to c, which has one, two, or more,
suitably formed points or knife-edged projections on its under side, and which
rest in conical, curved, or other formed steps. These are shewn to an enlarged.
scale in Figure 4. e, e, is a balance weight, attached to the framework, which
may be readily moved up and down the rod to which it is fixed, and which;
gives the power of regulating or setting the instrument to the greatest
exactitude; or the segment of a circle, properly divided, and moving before;
a fixed pointer, may be substituted. d, d, is a pointer or indicating hand, also:
attached to the framework c, and moving in front of a properly divided dial
plate ff; b, b, is a bracket or other suitable framework on which the whole
instrument rests. It will be seen, when the points or projections are placed.
in the recesses of the framework b, the instrument easily oscilate or vibrate
backwards and forwards with no other friction than that between the points
or knife edges, on which it is supported, and the cups or recesses, in which
the points or knife edges rest.
The action of the instrument represented at Figure 1 is as follows:-Any.
increase in the pressure of the atmosphere forces the mercury or. other fluid up
the tube, as in the ordinary barometer. This increased weight (equal to the
quantity of the mercury or other fluid), moved to the opposite side of the point
of suspension, causes the instrument, which is balanced on its points or other-
wise suspended, to move, and the indicating hand shews, on a properly divided
dial or scale the change. A decrease in the pressure of the atmosphere affects the
instrument in exactly the opposite direction. A scale may be fixed to the tube,
a, a, which will give an indication of the rise and fall of the mercury, as the.
ordinary barometer does.
To.compensate for the change of temperature in the column of mercury or
other fluid used in this instrument, I fix a thermometer or other suitably
formed tube containing a fluid (but I prefer to use an ordinary thermometer,
as it will serve to shew the temperature), placed diagonally on the framework
1

page_text: or suspended portion of the barometer, having its stem placed at an opposite
"angle to the large tube, or in any convenient position, as shewn in the dotted
lines. As the temperature of the atmosphere'in which the barometer is placed
rises or increases, it has the effect of expanding the mercury in the suspended
tube, which causes the instrument to indicate an increase in pressure, which is
erroneous; the thermometer compensation rectifies this erroneous indication
in the following way:-The same temperature that causes the mercury or
other fluid in the barometer tube to expand, also causes the mercury or other
fluid in the thermometer tube to rise, and I so arrange the area of the
thermometer tube, or the angle at which it is placed; as that an equal weight
of mercury or other fluid shall be thrown or forced to the opposite side, or up
the tube of the thermometer, and this acts. as an exact counterweight, to the
erroneous indication of the barometer itself, so that in this way. I am enabled
to produce an instrument which will itself accurately indicate the changes in
atmospheric pressure, and not be affected by: temperature, as ordinary
barometers are. I can also use a metallic compensation. In other words, I
arrange my instrument so that the temperature acts equally on both sides, and
thus destroys its injurious effects on the accuracy of my indication of pressure.
I may here mention that I can apply the same arrangement to the various
instruments of my Invention requiring such a compensation, and, it will be
unnecessary to describe: this attachment to each: The compensation need not
be applied unless when great accuracy is required in the indications, as the
instrument, without any compensation, will act as accurately as the. best
barometers of the usual construction. Figure 6 represents a front elevation,
Figure 7 an end elevation, and Figure 8 a plan, of another arrangement of
my improved barometer. a, a, is a syphon tube, containing mercury or other
fluid, closed at one end m, and having an elastic:or flexible top or diaphragm.h
at the other end; it is shewn supported. on points, as before described; the
tube may be filled with the fluid used to the height indicated by the lines n; o.
This form of the instrument does not require any compensation, for the
fluid used is acted upon equally. on each side of the. point of 'suspension by
temperature, and the quantity of air in each side of the tube being also the
same, a similar effect is produced on each side, but any change in the pressure
of the outer atmosphere can be readily communicated to the fluid within
through the flexible or elastic top or diaphragm h.
.
A
Figure 9 represents an end élevation, Figure. 10 a front elevation, and
Figure 11 a plan, of another arrangement of my improved* barometer.
flexible diaphragm-u is fitted air-tight over a recess.s; two or more rods are
attached to the recess, and support, or are attached to a crosshead vand pass:

page_text: through the framework.e; to the, top of the diaphragm-u a rod is made fast,
which rod is prolonged and carried through the crosshead v; a spring is
then placed on the end of this rod and a weight k fixed outside the spring.
In making fast this weight k; the spring is compressed between it and the
crosshead v, and the pressure of the spring thus confined draws the diaphragm u
forward, producing a vacuum inside the chambers, till it is balanced by the
pressure of the atmosphere; any change taking place in the pressure of
the atmosphere has a tendency to move the diaphragm either out or in,'
and each such change causes a variation in the distance of the weight l
from the point of suspension, and gives motion to the indicating hand d.
Figure 12 represents a section, and Figure 13 a front elevation, of another
construction of my improved barometer. A cistern q is formed by having a
recess or cavity in the base piece m. In the upper side of m a glass or other
tube a is made secure, the tube a and cavity or chamber q is filled with the
fluid to be used, and a flexible diaphragm o of any suitable material is made
at the bottom of the chamber q by taking a light washer and fixing the flexible
substance between it and the case m; a screw or stud p is fixed to the
diaphragm o, a spring n, n, is then placed below the diaphragm, and the
screw or stud p attached to the diaphragm passes through the spring, and by
a nut screws up or presses against the spring; this draws the diaphragm down,
and the fluid in the tube and chamber with it, and a vacuum is formed in the
upper portion of the tube a;, the spring and liquid is held in balance by
the atmosphere, and any change in its pressure causes the fluid in the tube a
either to rise or fall, and a scale f being fixed to the tube a, the variation can
be at once observed. Any other form of spring or other substitute may be
used for drawing and holding the flexible diaphragm down, and this instru-
ment may either be used suspended, as represented in Figure 21, or stationary,
as in Figure 13.. I produce a similar action in various ways; for instance, in
Figure 6 the diaphragm and spring may be placed where the flexible cover h
is shewn, and the vacuum produced at m; a tube of smaller diameter may
also be used at the top of the barometer tube, and a lighter fluid placed'
in the top of the mercury when a long range of indication is required, and
this arrangement may either be suspended or stationary. Figure 19 repre-
sents this arrangement as a stationary instrument, with a scale to both the
large and small tube; and Figure 20 represents the same construction of
instrument suspended or supported on points. Figures 14 and 15 represent
an end and front elevation of another arrangement of my improved barometer.
a is a hollow tube, thin and flexible, exhausted of air; d is a solid rod of
suitable weight to balance the tube a; the hand of indication d and the balance

page_text: weight e are also attached, and supported on points on the pillar 6; an increase
or decrease of pressure in the atmosphere causes the exhausted tube a to coil
or uncoil, which throws the weight a greater or less distance from the point
of support; by this means the instrument oscilates, and the hand d shews on
the dial the change. Figure 23 represents a variation of this same arrange-
ment. Figure 16 represents a differently formed tube a, acting in the same
manner, and supported instead on a bracket b. Figure 17 represents another
arrangement, having for the moving part a corrugated conical tube a, a; this
tube is exhausted of air, and the increase or decrease of atmospheric pressure.
causes the tube to become more or less corrugated, and the weight, by reason
of the tubes' conical form, is then thrown unequally on the point of support, and
the hand or pointer indicates accordingly. Figure 18 represents another
arrangement of my improved barometer. a, a, is a curved conical tube exhausted
of air; the change in the pressure of the atmosphere causes the tube to coil or
uncoil, and as its length is unequally placed, the weight is moved unequally
from the point of suspension, and the hand indicates accordingly. Figure 26
represents another variation of this same arrangement; in this instance the
tube is not conical but is supported unequally. Figure 22 represents another
arrangement, in which the exhausted tube is of a circular, coiled, or screw form;
the increase or decrease of pressure causes the tube to become more or less
lengthened, and the action is indicated by the hand. Figures 24 and 25
represent forms of my barometer suspended by thin steel or other suitable
rods or wires, or silken cords, the action is the same as previously described.
Figure 27 represents one of my improved barometers with the thermometer
compensation previously referred to. Another arrangement is represented at
Figure 28. a, a, is a tube, on the end of which a flexible diaphragm is made
fast; to the diaphragm a rod is attached, having a weight at its end; the
weight may be either supported by a silken cord or other flexible material
from the top of the tube, or a roller, as shewn by the dotted lines, may be
used instead of the cord support. The tube is exhausted of air, and the action
of the atmosphere on the diaphragm causes it to move out and in and with
it the weight; this alteration of its position relative. to the point of support,
causes the instrument to move and the indicating hand with it. When any
of these instruments are required for marine purposes, they may, if desired, be
suspended from gimbals or other suitable supports; and it is apparent, from the
description I have given, that the instruments, carrying out this Invention,
may be made in a very great variety of ways; but it is unnecessary for me
further to enter into detail. The instruments may have the points below on
the bracket or support, and the cups or recesses above, on the frame or moving

page_text: part of the instruments, or on horizontal bearings, or journals; or a horizontal
shaft or spindle carrying the instrument and framework may have recesses or
conical concave cups, in which points or supports may be inserted; or the ends
of the spindle may terminate in a point working in properly constructed conical
cups; where accuracy is required agate or jewelled cups may be used. Two
or more of any formed or shaped instruments, on the principle described, may
act by one indicator and give the mean pressure of the atmosphere.
And I would have it understood that I do not confine myself to the precise
details so long as the peculiar character of the Invention be retained; but I
claim,
First, the various arrangement of instruments for indicating the variation in
the pressure of the atmosphere or other fluids, when suspended, supported, or
balanced as described, or when so disposed as to be acted upon by gravity.
Second, the mode of compensation for variations in temperature as described.
Third, the use of a lighter fluid above the one used (as described) when a
long range of indication is required.
In witness whereof, I, the said Henry Mapple, have hereunto set my
hand and seal, this Thirty-first day of October, in the year of our Lord
One thousand eight hundred and fifty-six.
זממוג זימזמIז
HENRY
IMA
MAPPLE (L.S.)