An Improved Barometer
Year: 1890

page_text: Date of Application, 13th Oct., 1890
Complete Specification Left, 7th July, 1891-Accepted, 8th Aug., 1891
PROVISIONAL SPECIFICATION.
An Improved Barometer.
ARTHUR MERVYN LANGDON New College Oxford Student and ALFRED
LANGDON Clerk in Holy Orders Vicarage Sleaford Lincolnshire do hereby
declare the nature of this invention to be as follows:-
A mercurial barometer with tube of small bore bent into convenient shape to
sustain an oblique arm at top which arm being about 6 or more inches in length
shall rise through the perpendicular height of over an inch and shall be furnished
with pointer and scale marking the tenth and hundredth parts of the said inch.
The lower end of the tube shall be inserted in a movable bottle of mercury formed
so as to present a large surface of the metal but holding comparatively little. This
bottle must be capable of being raised or lowered by a screw so that the height of
the oblique arm above the mercury may vary in the number of inches the said No.
being duly recorded by a pointer & the weather indications of each inch being
shewn in turn beneath the scale. By another screw behind the bottle the instrument
may be adjusted to sea-level.
Dated this Fourth day of October 1890.
ARTHUR MERVYN LANGDON.
ALFRED LANGDON.
COMPLETE SPECIFICATION.
An Improved Barometer.
ARTHUR MERVYN LANGDON Student of New College Oxford ALFRED
LANGDON Sleaford Lincolnshire Clerk in Holy Orders 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:-
The barometer consists of a small-bore tube of glass upright for some distance
from the base and rather more than 31 inches in total perpendicular height after
being bent into convenient shape and being made to terminate in an oblique arm of
any required pitch according to the degree of sensitiveness desired.
The tube being carefully filled with mercury has its lower and open extremity
immerged in a long shaped vessel containing the same metal.
The oblique arm is furnished with a scale shewing the decimal parts of an inch
through which the mercury in the said arm rises or falls in perpendicular height.
The tube is fastened on a frame of wood or other material and at the back of
this there is another frame which is raised or lowered by means of a screw and
which carries with it I the bottle or reservoir of mercury on its lower extremity
Il a pointer or index which moves on the face of the instrument and shews how
many inches of perpendicular height lie between the surface of the mercury in the
reservoir and the beginning of the scale III a series of weather indications which
can be seen in succession through a slit or opening in the face.
If the mercury in the oblique arm rises above the scale the reservoir is then to
be lowered till the index points to the next inch below that at which it formerly
stood (this inch being numerically higher than the former one above it) so that the
mercury will now be rising or falling-according to the atmospheric pressure,-
within the limits of the scale.
If on the other hand the mercury in the tube-which of course is sealed at the
top-falls below the scale the reservoir is raised till the pointer reaches the next
inch above that at which it previously stood but the inch numerically lower.

page_text: By this plan with a comparatively short oblique arm great sensitiveness and
correctness of reading is secured the hundredth part of an inch of perpendicular
rise or fall being clearly apparent without a vernier.
By altering the length of the back frame which carries the reservoir by a screw
or other means the instrument may be at once adjusted to sea-level whatever may
be the height of the place where it is used.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
I. The altering the height of the reservoir of mercury relative to the tube and
scale so that a short oblique arm will serve for any height of the barometric column
of mercury.
II. The causing to appear on the face of the instrument the special weather
indications which belong to that range within which the mercury for the time being
stands.
III. Adjusting the instrument to sea-level by altering the length of the back
frame and without altering the quantity of mercury employed.
Dated this Fourth day of July 1891.
ARTHUR MERVYN LANGDON.
ALFRED LANGDON.