CERTAIN IMPROVEMENTS IN BA- ROMETERS, PART OF WHICH INVENTION IS APPLICABLE TO THE REGISTRY OF OTHER FLUCTUATIONS THAN THOSE OF BAROMETERS
Year: 1853

page_text: LETTERS PATENT to David Stephens Brown, of Number 2,
Alexandrian Lodge, Old Kent Road, in the County of Surry,
Gentleman, for the Invention of "CERTAIN IMPROVEMENTS IN BA-
ROMETERS, PART OF WHICH INVENTION IS APPLICABLE TO THE REGISTRY
OF OTHER FLUCTUATIONS THAN THOSE OF BAROMETERS."
Sealed the 20th April 1853, and dated the 31st January 1853.
PROVISIONAL SPECIFICATION left by the said David Stephens
Brown at the Office of the Commissioners of Patents, with his
Petition, on the 31st January 1853.
I, DAVID STEPHENS BROWN, of Number 2, Alexandrian Lodge, Old
Kent Road, in the County of Surry, Gentleman, do hereby declare the
nature of the said Invention for "CERTAIN IMPROVEMENTS IN BAROMETERS,
PART OF WHICH INVENTION IS APPLICABLE TO THE REGISTRY OF OTHER FLUC-
TUATIONS THAN THOSE OF BAROMETERS," to be as follows, namely:-
A contrivance by which the tubes of barometers may be reduced in
length. Do. for rendering that kind of barometer called a sympesometer

page_text: or thermo barometer self-acting, thereby dispensing with the use of
a thermometer which now accompanies it. Do. for increasing the scale
or range of barometers. Substituting the present weather tables of
barometers for one of probabilities. A means of registering the fluc-
tuations of barometers, which may also be applied to register other
fluctuations than those of barometers. Do. for economizing the liquids
used in making barometers by the employuient of a peculiarly shaped
used in making barometers by the employuient of a peculiarly shaped
tube.
ADDITION TO PROVISIONAL SPECIFICATION.
I, DAVID STEPHENS BROWN, of No. 2, Alexandrian Lodge, Old Kent
Road, in the County of Surry, Gentleman, do hereby declare the
nature of the said Invention for "CERTAIN IMPROVEMENTS IN BAROMETERS,
PART OF WHICH INVENTION IS APPLICABLE TO THE REGISTRY OF OTHER
FLUCTUATIONS THAN THOSE OF BAROMETERS," to be as follows:-
A contrivance by which tubes of barometers may be reduced in
length, which is done by causing a weight or spring to act on their
cisterns. Also for increasing the ranges or scales of barometers, which
is done by employing tubes of unequal bores, & peculiarly bent or
curved, and using two immiscible liquids of nearly equal specific gravi-
ties. Also for rendering that kind of barometer called a sympesometer
self-acting, thereby dispensing with the use of a thermometer which
now accompanies it, which is done by the addition of a liquid bulb to
counteract the effects of temperature on the air bulb of such instru-
ment. Also for registering the fluctuations of barometers, which is donc
by means of a perforated table, or one made double, having pins or
strings of different colors. Substituting the present weather table for
one of propabilities, or one that shows the relative proportions in figures
of the quantity of rain which falls with the height of the fluid in the
instrument as set to any particular elevation, &c.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said David Stephens Brown in the Great Seal Patent
Office, on the 27th July 1858.
"
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
DAVID STEPHENS BROWN, of Number 2, Alexandrian Lodge, Old Kent
Road, in the County of Surrey, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirty-first day of January, in the
year of our Lord One thousand eight hundred and fifty-three, in the
sixteenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said David Stephens Brown, Her special
license that I, the said David Stephens Brown, my executors, 'adminis-
trators, and assigns, or such others as I, the said David Stephens
Brown, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after 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 "CERTAIN IMPROVEMENTS IN BAROMETERS, PART OF WHICH
INVENTION IS APPLICABLE TO THE REGISTRY OF OTHER FLUCTUATIONS THAN
THOSE OF BAROMETERS," upon the condition (amongst others) that I, the
said David Stephens Brown, 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 David Stephens Brown, 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, with the aid of the Drawings therein
referred to (that is to say):
It consists of a contrivance by which the tubes of barometers may be
reduced in length, which I accomplish by causing a weight or spring

page_text: to act on their cisterns. Figure (1.) in the two copies of the Drawings
which accompany this Specification represents a barometer of this
construction, (a,) being the tube, (b) the cistern, of a cylindrical form,
the blue part represents the liquid employed for the purpose of indica-
tion, &c. To the bottom of the cistern is attached the weight (c)
which should be in amount proportionate to the area of the bottom of
the cistern and the reduced length of the tube. The cistern is air-tight,
and that part of it marked red is flexible or elastic, so as to allow it to
collapse and distend by the action of the atmosphere, which will have
the effect of causing the liquid to rise and fall. in the said tube. Inside
the cistern are placed the two cylinders (d,) and (e) which slide one
into another, like the parts of a telescope; the lower one has a bottom,
and their use is to prevent the sides of the cistern from collapsing
Interally. At the part of the cistern where the flexible part joins the
non-flexible some liquid is placed round the joint externally, in order to
prevent the possibility of any air intruding itself into the cistern, as
shown in the Drawing. Instead of the weight (c) a spring may be
substituted, one end of which should be attached to the bottom of the
cistern, and the other end to some fixed point on the frame of the
barometer in the direction (f). The next improvement is a coll-
trivance for rendering that kind of barometer called a sympesometer
self-acting, thereby dispensing with the use of a thermometer which now
accompanies it, and which I accomplish by adding to it a liquid bulb or
cistern to counteract the effects of temperature on the air bulb. Figure
(2.) represents such an instrument, (a 2,) being the air bulb, (b 2,) being
the tube for observation, (c 2,) the liquid bulb or cistern, (d2,) a tube
connected therewith, and open at the top so as to permit the action of the
atmosphere,, any change in the pressure of which will be indicated by
the rising or falling of the fluid in the tube (62); but the instrument is
not affected by changes of temperature, because the expansion of the air
or gas in the bulb (a 2), caused by heat, will be compensated by a like
expansion of the liquid in the bulb (c2), which will mount up in the
tube (2,) to a sufficient height to balance the increased pressure in the
bulb (a 2). In this instrument two liquids are used, namely, alcohol
and mercury; the former is represented by a red color, and the latter

page_text: by blue, by means of which a scale nearly twice as open is obtained as
when mercury alone is employed, unless the tube (d2,) were of greater
bore than the tube (62). The proportionate sizes that the tubes and
bulbs should bear to each other will depend upon the nature of the
fluids used, and must be calculated according to their different degrees
of expansibility. The arrangement may be slightly varied by enclosing
the greater part of the air contained in the bulb (a 2,) in a small air-
tight flexible or clastic bag, and filling the remainder of the said bulb
with water, oil, or alcohol, &c., and the bulb (c 2,) with mercury only,
the two fluids meeting each other in the tube (62,) where their
junction would form the index; the range of the barometer, however,
would then only be half as great as in the former case, unless the tube
(d 2,) were of greater bore than the tube (62). The next improvement
is for increasing the ranges or scales of barometers, which is done by the
employment of a tube of unequal bore, and the use of two immiscible
liquids of nearly equal specific gravitics, such as water and oil, the one
being coloured, or of a different color to the other. Figure 3, represents
such an instrument, (a 3,) being the tube, and (63,) the cistern; the parts
marked red and blue represent the two immiscible liquids, and their
junction forms the index. Supposing the bore of the larger part of the
tube to have an area ten times as great as the smaller part, it is evident
that for every inch the liquid rises or falls in the former it will rise or
fall ten inches in the latter, and hence by this arrangement the scale of
a barometer, instead of being confined to the top of the tube, may be
extended nearly over its whole length, and if a moveable piston were
placed in the smaller part of the tube it would serve as an index, and
in that case one fluid would suffice. The scale of the barometer may
be still further increased in length by making the tube in the form
represented by Figure 4, or in a semicircular or spiral onc. The next
improvement is a contrivance for registering fluctuations of barometers,
&c., and consists of a table made of two sheets of paper placed parallel
and at a short distance from each other, and by the employment of
pins and strings of different colors; on one of the sheets of paper is
printed a táble to be used for registration, having the dates on the top,
and the scale or table, of the barometer on one side, as shown by

page_text: Figures 5, and 6, the former being a front and the latter a side view of
such table; and Figures 7, and 8, are views of the said pins. When it
is intended to register the fluctuations of the barometer by such table,
one of the pius is to be placed in the column immediately under the
clate, and opposite the elevation of the fluid, as shown by the red pin
(a 4,) Figure 5, under the 4 Jan, and opposite 30 inches in. the baro-
metrical scale. The reason why two sheets of paper are used in the
construction of this table is, that the pins may be supported in a
horizontal position, as will be seen by reference to (a 5,) Figure 6, where
a red pin is shewn to be so supported. The use of pins of different
colors is to shew the comparative fluctuations. of different years, a
different coloured pin representing every different year, or to distinguish
any other difference, 'sucli as the rainy from the fine days, &c., and the
use of strings of different colors is for the same purpose, as represented
by the blue string (64,) Figure 5, which extends along the whole of
the blue pins, passing under one and over the other, and is tightened
by the small weight (c-4,) at one of its extremities. The sheets of paper
are to be fixed in a frame, and made sufficiently yielding to be pierced
by the pins; or the table may be made of solid wood or. metal, and
perforated with numerous holes over its surface, into which the pins
may be placed. The table may or may not be attached to the baro-
meter, and by substituting its scale or table for that of any other, or for
a list of prices, &c., it may be used for registering other fluctuations
than those of barometers. At the bottom of the said table is placed a pin-
cushion to keep a supply of pins for use, as shown by the letter (d4).
The last improvement consists in substituting for the words fair, rain,
stormy, &c., which form the present weather table of the barometer, a
table of probabilities, or one which gives an estimate of the quantity of
rain which may be expected to fall at any particular elevation of the
liquid of the barometer, which I accomplish by placing a double row of
figures by the side of the figures that indicate the height of barometrical
fluid, one row showing the extent of time that it rains, and the other
that it does not rain; (a 6,) Figure 9, represents such a table, which,
however, is quite an arbitrary one as regards the figures, which will vary
with the elevation and locality, and will have to be determined by a

page_text: course of observations as to how many seconds it rains, and how many
it does not, at every degree of elevation of the fluid in the barometer.
In witness whereof, I, the said David Stephens Brown, have here-
unto set my hand and seal, this Twenty-seventh day of July,
in the year of our Lord One thousand eight hundred and fifty-
threc
D. S. BROWN. (L.S.)