IMPROVEMENTS IN BAROMETERS AND. APPARATUS CONNECTED THEREWITH
Year: 1877

page_text: LETTERS PATENT to Frederick Bogen, of No. 17, Adelaide Road, N.W., in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN BAROMETERS AND.
APPARATUS CONNECTED THEREWITH."
Sealed the 7th December 1877, and dated the 30th June 1877.
PROVISIONAL SPECIFICATION left by the said Frederick Bogen at the Office
of the Commissioners of Patents on the 30th June 1877.
FREDERICK BOGEN, of No. 17, Adelaide Road, N.W., in the County of Middlesex.
"IMPROVEMENTS IN BAROMETERS AND APPARATUS CONNECTED THEREWITH."
This Invention has for its object improvements in barometers and apparatus con-
nected therewith.
The construction of my new barometer is such that the barometer can easily be
put together and taken again to pieces in a few minutes, and that it occupies little
space, and affords great security and convenience in travelling.
The long leg of the siphon consists of a tube of the same diameter throughout,
closed at one end, and supplied with a wooden cleaning rod and with a glass stopper,
which has a fine hole passing through its centre at the other end. The tube can be
filled with quicksilver in about one minute; the stopper is then inserted, and the
hole through the stopper being closed by the finger the tube is inverted, and a
portion of mercury allowed to flow away to produce a vacuum. The tube is then
brought to a horizontal position, and moved gently to and fro to allow all air to rise
freely, if there should be any, to the upper side of the tube, and by gently inclining
the tube the bubbles of air, if there are any, will be made to unite and travel
upwards along the tube, and allowed to escape at the top; the tube is then refilled
to the brim. By this a perfect vacuum can be obtained, such as could hitherto only
be produced by an air pump.
The short leg of the siphon is of the same diameter as the long leg, and is formed
with a semicircular bend at one end. At the end of this bend is a socket to receive
the open end of the long leg. The open end of the long leg is ground to fit air-
tight into the socket, so that the long and short legs can be instantaneously put
together or separated. The long leg having been filled with quicksilver, as above

page_text: described, and the short leg having also been partly filled, the socket of the short
leg is placed over the open end of the long leg. The siphon so formed is then
brought gently to a horizontal position to unite the columns of quicksilver in the
two tubes, and with proper manipulation all air can be excluded or extracted from
the long limb.
The barometer is mounted in a stand composed of a small bed with three legs
radiating from it, each carrying an adjusting screw. From the outer ends of the
radiating legs rise three armis, which unite together at their upper ends, and clasp
and support the long upright leg of the siphon. The short curved leg of the siphon
has cemented to it at the bottom a small pivot concentric with the long tube to
enter a corresponding socket in the bed. This stand affords not only the best and
safest means of placing the barometer into a vertical position, but also completely
prevents it from being moved by wind.
Upon the top of the short leg of the siphon is secured a cap, through which
passes a finely-threaded screw of a given length, carrying at its lower end an ad-
justable point, and having at its upper end a graduated disc, with an index point
to come opposite a scale on the long leg. By turning the screw and bringing this
point down to the surface of the quicksilver, and then turning the siphon in its
support, it can easily be seen whether the level of the quicksilver remains the same,
or if not, it can be seen in which direction the siphon inclines, and any error
can be quickly corrected by the adjusting screws of the stand. By means of this
screw also a more perfect and precise reading can be obtained than was hitherto
practicable.
By a peculiar contrivance, such as a white or light green paper disc, with a small
hole in its centre, placed over a common lens, a perfection in the reading at the
upper end of the mercurial column can also be obtained, which is likewise entirely
new, and avoids the error of parallax.
For reading off at the upper end of the mercurial column I also use a tube
embracing and sliding on the long leg. The tube has two slots on opposite sides to
allow the mercurial column to be seen. Down both sides of both slots are graduated
scales, with the peculiarity that the scales are graduated on both sides. By this
means a very accurate reading can be secured, and the error of parallax completely
avoided.
Two thermometers (an inner and outer one) are suspended from a ring which
supports the three arms against the long leg of the barometer, and affords a very
simple and correct method of ascertaining the true temperature of the mercury as
well as of the surrounding air.
:
For indoor work, instead of the tripod a short board may be used, which is sus-
pended from the wall and serves as a stand for the barometer, affording not only
the advantage of a quick and accurate adjustment, but, owing to a pivot placed at
the centre of gravity of the instrument and screwed through the board into the
wall, supplies a ready means of turning the barometer into any angle of the
quadrant, so as to fill the vacuum after every observation and inspect it when
required. This practice I consider necessary to ensure correct measurement in the
height of the mercurial column of barometers, and is the only means of avoiding the
prejudicial depression caused by the mercurial vapor.
I also construct cistern barometers upon the same principle as that herein-before
described, and mount them upon the same stands, so that the correct levelling can be

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederick Bogen in the Great Seal Patent Office on the 29th December
1877.
FREDERICK BOGEN, of No. 17, Adelaide Road, N.W., in the County of Middlesex.
"IMPROVEMENTS IN BAROMETERS AND APPARATUS CONNECTED THEREWITH."
This Invention has for its object improvements in barometers and apparatus con-
nected therewith.
The construction of my new barometer is such that the barometer can easily be
put together and taken again to pieces in a few minutes, and that it occupies little
space, and affords great security and convenience in travelling.
The long leg of the siphon consists of a tube of the same diameter throughout,
closed at one end, and supplied with a wooden cleaning rod and with a glass stopper,
which has a fine hole passing through its centre at the other end. The tube can be
filled with quicksilver in about one minute; the stopper is then inserted, and the
hole through the stopper being closed by the finger the tube is inverted, and a
portion of mercury allowed to flow away to produce a vacuum. The tube is then
brought to a horizontal position, and moved gently to and fro to allow all air to rise
freely, if there should be any, to the upper side of the tube, and by gently inclining
the tube the bubbles of air, if there are any, will be made to unite and travel
upwards along the tube, and allowed to escape at the top; the tube is then refilled
to the brim. By this a perfect vacuum can be obtained, such as could hitherto
only be produced by an air pump.
The short leg of the siphon is of the same diameter as the long leg, and is formed
with a semicircular bend at one end; at the end of this bend is a socket to receive
the open end of the long leg. The open end of the long leg is ground to fit air-
tight into the socket, so that the long and short legs can be instantaneously put
together or separated. The long leg having been filled with quicksilver, as above
described, and the short leg having also been partly filled, the socket of the short
leg is placed over the open end of the long leg. The siphon so formed is then
brought gently to a horizontal position to unite the columns of quicksilver in the
two tubes, and with proper manipulation all air can be excluded or extracted from
the long limb.
The barometer is mounted in a stand composed of a small bed with three legs
radiating from it, each carrying an adjusting screw. From the outer ends of the
radiating legs rise three arms, which unite together at their upper end. and clasp
and support the long upright leg of the siphon. The short curved leg of the siphon
has cemented to it at the bottom a small pivot, concentric with the long tube, to
enter a corresponding socket in the bed. This stand affords not only the best and
safest means of placing the barometer into a vertica! position, but also completely
prevents it from being moved by wind.
Upon the top of the short leg of the siphon is secured a cap, through which
passes a finely-threaded screw of a given length, carrying at its lower end an ad-
justable point, and having at its upper end a graduated disc, with an index point
to come opposite a scale on the long leg. By turning the screw and bringing this
point down to the surface of the quicksilver, and then turning the siphon in its
support, it can easily be seen whether the level of the quicksilver remains the same,
or if not, it can be seen in which direction the siphon inclines, and any error
can be quickly corrected by the adjusting screws of the stand. By means of this
screw also a more perfect and precise reading can be obtained than was hitherto
practicable.
By a peculiar contrivance, such as a white or light green paper disc, with a small
hole in its centre, placed over a common lens, a perfection in the reading at the
upper end of the mercurial column can also be obtained, which is likewise entirely
new and avoids the error of parallax.
For reading off at the upper end of the mercurial column I also use a tube

page_text: :
embracing and sliding on the long leg. The tube has two slots on opposite sides to
allow the mercurial column to be seen. Down both sides of both slots are graduated
scales, with the peculiarity that the scales are graduated on both sides. By this
means a very accurate reading can be secured, and the error of parallax completely
avoided.
Two thermometers (an inner and outer one) are suspended from a ring, which
supports the three arms against the long leg of the barometer, and affords a very
simple and correct method. of ascertaining the true temperature of the mercury, as
well as of the surrounding air.
For indoors work, instead of the tripod a short board may be used, which is sus-
pended from the wall, and serves as a stand for the barometer, affording not only
the advantage of a quick and accurate adjustment, but, owing to a pivot placed at
the centre of gravity of the instrument, and screwed through the board into the
wall, supplies a ready means of turning the barometer into any angle of the quadrant,
so as to fill the vacuum after every observation, and inspect it when required. This
practice I consider necessary to insure correct measurement in the height of the
mercurial column of barometers, and is the only means of avoiding the prejudical
depression caused by the mercurial vapour.
I also construct cistern barometers upon the same principle as that herein-before
described, and mount them upon the same stands, so that the correct levelling can be
readily obtained.
In order that my Invention may be most fully understood and readily carried
11
1.
Figure 1 represents the travelling siphon barometer mounted on its stand, and
drawn to half of its natural size.
a, a, is the long leg of the siphon; b is the short or bent leg, with the socket to
receive the open end of the long-leg a, a. The construction of both legs is shown
in the sectional Drawing, Figure 1. c is the cleaning rod; it has an air hole through
the centre of its upper end, indicated by dots. This rod is used to clean the tube a
before mounting the instrument. d is the glass stopper with a fine hole through its
centre.
The barometer is mounted on a wooden stand, but I also construct these stands
of malleable cast steel. e is the small bed, with three legs radiating from it,
carrying the three adjusting screws f. From the outer end of the legs rise the
three arms g, which unite together at their upper ends, and clasp and support the
long upright leg by means of a ring, which at the same time carries the two
thermometers, one of which stands in a glass tube filled with mercury (called the
inner thermometer) whilst the outer one is surrounded by a glass tube with a hole
through the bottom, and the cork to admit the free air passing around the bulb of
the thermometer. i is a brass cap, through which passes a finely-threaded steel
screw x, with a graduated disc y at its upper end divided into ten equal parts, and
bearing a hollow hand z, which turns freely over the disc without touching the
graduation; this screw is used to read the lower level.
In order to insure a given standard length of the screw x, its lower point termi-
nates in an adjustable small screw o. The extreme point of the hand is a round
steel pin, pointed and turned upwards at one end, whilst the other slides in the
hollow hand, and can be drawn out or pushed in, so as to suit the bend of the short
leg of other barometers, and stand close to the barometrical tube and the scale
etched thereon. Opposite to the hand the tube a is graduated for a distance of,
say, seven or eight centimetres, with a scale of half millimetres, and the pitch of
the screw is such that one revolution corresponds to a division of the scale.
The reflecting lenses and are two differently shaped common lenses suitable
'for reading the scale, as they are supplied with white or light green paper discs and

page_text: peculiar shaped holes in their centre; by their aid the scale can readily be read to
the tenth of a millimetre.
The reflecting sliding cylinder m is made to slide over the barometrical tube. It
has two slots cut out opposite to each other, on the sides of which are secured two
narrow strips of silver plate, each of which is graduated on both sides to a scale,
say, of half millimetres. One of the sides is visible by reflection from the quick-
silver, where it is in contact with the glass tube, the other by direct vision, thus
securing a very correct and clear reading of the line of contact of the mercury with
the glass.
The reading is greatly aided by the reflected light from the white colored reflecting
lens disc, which illuminates the scale at the same time that it. augments the figures
in size. This graduated standard slide has besides the advantage of doing away
with the finer divisions of the scale etched on the. barometrical tube, the fine
etching being a more costly operation than having them on the slide and less
accurate. The etched divisions on the barometer tube may at this part be five
centimetres or even further apart, and the slide is set to them wherever it may be
required.
The third advantage of using the slide consists in being able to inspect the scale
of every barometrical tube, and detect every inaccuracy committed by the maker
with extraordinary facility.
Figure 2 shows the manner in which this siphon standard barometer can be used
for indoor work, and how the tube is made to turn on a pivot a placed almost at the
centre of gravity of the instrument, and screwed against the swinging board b and
the wall board c.
Figures 3 and 4 represent the natural size (in front and side view) of a siphon
cistern. This new form participates of both kinds of known barometers, possessing
a decided advantage over either. This cistern can be used for every barometrical
tube, and it mounts on either of the above-described stands of Figure 1 and
Figure 2.
A is a glass box formed of four glass plates cemented into an iron bottom plate m,
and held together by iron bands i, i, at the four sides, which cover the corners of
the case and their top part. The lid of the cistern is an iron plate screwed against
a block of wood d, which fits closely into the cistern, and fills up about three-
quarter parts of its capacity. By this contrivance the mercury is forced into a
narrow front space c, which serves as a siphon, being connected with the mercury
of the barometrical tube by a channel scooped out from the lower end or bottom
part of the block of wood, as seen shaded dark in Figure 4, when the filled tube,
after being inverted and placed on the stand, is raised off the bottom plate by
turning the adjusting ring c. Any excess of mercury, when great heights are
determined, is allowed to flow off by the steel tube k, k, into the bottle. This
tube k when pushed up into the cistern serves as an air hole, and can be filled with
a blotting paper spiral saturated with chloride of calcium, and dried so as to
introduce perfect dry air into the siphon and keep the mercury bright. Into the
lid of the cistern is fastened the cylinder d'; its upper end is cut diagonally to fit
the lower cut of the adjusting ring e.
In setting up the instrument the inverted lid of the cistern with its block & is
placed over the filled barometrical tube, and the glass cistern placed over the block
and pushed down until the end of the barometrical tube touches the bottom plate m,
and the adjusting ring e comes in contact with the ring f. Figure 4, which is per-
manently fixed to the glass tube by shellac, and can easily be shifted by warmning
it. By turning the ring e the tube is lifted and the mercury is free to flow.
What I claim as my Invention of improvements in barometers and apparatus
connected therewith is the following:-
First. The straight barometrical tube, with an acurately fitting pierced glass
stopper to facilitate the extraction of the air in filling.
Second. The siphon barometer constructed of two legs ground air-tight, and so
to be put together or separated easily.

page_text: Third. The standard screw of a fine thread, with a graduated disc for reading the
lower level of the mercury.
Fourth. The reflecting sliding cylinder, with an interior and exterior scale of
graduation for reading the upper level.
'
Fifth. The cistern siphon, in which the mercurial surface is reduced and divided
into two columns by the insertion of a block or partition.
Sixth. The mounting on a pivot concentric with the longer leg of the barometer,
so, that by rotating it may be ascertained if the instrument is set truly upright.
Seventh. The mounting with a pivot near the centre of gravity of the barometer,
and with means for clamping, thereby admitting of the instrument being inclined to
fill the tube when out of use.
Eighth. The barometer stand folding together, and having three arms and three
legs, with adjusting screws for holding the barometer in a vertical position and per-
.mitting of its rotation, as shewn in Figure 1.
In witness whereof, I, the said Frederick Bogen, have hereunto set my hand
and seal, this Twenty-ninth day of December, in the year of our Lord One
thousand eight hundred and seventy-seven.
FRED. BOGEN. (L.S.)