An improved Barometer.
Year: 1896

page_text: Date of Application, 13th Nov., 1896
Complete Specification Left, 13th Aug., 1897-Accepted, 13th Nov., 1897
PROVISIONAL SPECIFICATION.
An improved Barometer.
I, HENRY GOOLD-ADAMS of Jamesbrook, Ballinacurra, Midleton, Co. of Cork,
Ireland, a Captain in the Royal Artillery do hereby declare the nature of this
invention to be as follows:-
A column of mercury or any other suitable liquid is supported by atmospheric
pressure in a tube of glass or other suitable material at the top of which column
there is a partial or imperfect vacuum which partial or imperfect vacuum supports
in its turn a second column of liquid with a second partial vacuum (if necessary).
& so on till the last partial vacuum supports a column of liquid only, with a
perfect vacuum at the top. There may be any number of columns from two
(with one partial vacuum) upwards, according to the degree it is desired to shorten
the height of the barometer. For convenience the columns are placed parallel
&, the pressures in the partial vacuums are so regulated that each column is of nearly
the same length at sea level when the thermometer is about 600° F. The pressure
of the atmosphere is ascertained by measuring & adding together the heights of
the several columns.
H. GOOLD-ADAMS, Capt. R.A.
An Improved Barometer.
I, HENRY GOOLD-ADAMS of the Royal Artillery Barracks, Weymouth, Dorset
a Major in the Royal Artillery do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:—
(1) A hollow tube of glass or other suitable material or materials of any
convenient bore open at one end is bent in three or more places so as to form
four or more parallel legs. The bends E and F and others when there are more
bends are strangled to prevent the passage of air bubbles and the leg A E is so
bent near the centre as to allow of the leg 1 H being in a straight line with the
upper portion of A E in order that the distance 1 A may at any time be read by
means of a scale. The column of mercury or other suitable liquid A E B is
supported by the pressure at B of the partial vacuum in the tube between B and C.
(2) The column C F D is supported by atmospheric pressure at 1) the end H
being closed with parchment or other suitable material so as to allow the air
to exert its pressure but to prevent the accidental passage of the mercury when the
instrument is being moved.

page_text: (3) The pressure of the atmosphere therefore exerted at the point D in supporting
the column DCF has to do so against the pressure of the partial vacuum in CB
or what is the same thing against the weight of the column of liquid A E B,
the space above A being a perfect vacuum; the added lengths therefore of the
two (or more) columns gives the pressure of the atmosphere at any moment.
(4) Also as the atmospheric pressure varies so will the lengths of the columns,
the point D moving up or down one half the total change in the length of the
column CFD & correspondingly the point A one half the change in A E B,
because as the points A & D rise so will the points B & C fall respectively, equal
amounts & vice versa, consequently the distance A D varies with the pressure
of the atmosphere & is a direct measure of it. This method only applies when
there are two columns as in the sketch as in this case alone is the measure A D a
measure of the pressure.
(5) The exhaustion of the partial vacuum C B when the instrument is made is
carried down to such a point that each of the columns (when mercury is used) is
of about 15 inches in length at sea level when the atmospheric pressure is normal
& when more columns are employed their respective lengths are correspondingly
shorter.
(6) The columns of mercury ar other liquid are prevented from mixing by a
diaphragm of parchment, cork or other suitable material inserted in the tube at I
& at similar places where there are other columns.
(7) Having now particularly described & ascertained the nature of my said
invention & in what manner the same is to be performed I declare that what I
claim is
I. An arrangement by which the pressure of the atmosphere may be ascertained
by combining together the lengths of two or more parallel columns of mercury
or other suitable liquid as herein before described.
II. In an arrangement as before described when consisting of two columns
of liquid only a means whereby the pressure of the atmosphere may be ascertained
in one operation.
Doted this 19th day of Aument 1807