CERTAIN IMPROVEMENTS IN INSTRUMENTS FOR TAKING, MEASURING, AND COMPUTING ANGLES
Year: 1850

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DONALD
BEATSON, of Green Street, Stepney, in the County of Middlesex, Mariner,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent, under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-ninth day of
January, One thousand eight hundred and fifty, in the thirteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Donald Beatson, my exors, adiñors, and assigns, Her especial
licence, full power, sole privilege and authority, that I, the said Donald
Beatson, my exors, adiñors, and assigns, and such others as I, the said
Donald Beatson, my exors, adññiors, or assigns, should at any time agree
with, and no others, from time to time and at all times during the term of
years therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, and in
the Islands of Jersey, Guernsey, Alderney, Sark, and Man, and in all Her
said Majesty's Colonies and Plantations abroad, my Invention of "CERTAIN
IMPROVEMENTS IN INSTRUMENTS FOR TAKING, MEASURING, AND COMPUTING ANGLES;"
in which said Letters Patent is contained a proviso, that I, the said Donald
Beatson, should cause a particular description of the nature of my said
Invention, and in what manner the same is to be performed, by an instrument
in writing under my hand and seal, to be inrolled in Her said Majesty's.
High Court of Chancery within six calendar months next and immediately

page_text: after the date of the said in part recited Letters Patent, as in and by the
same, reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Donald Beatson, hereby declare that the nature of my said Invention, and
in what manner the same is to be performed, are fully described and
ascertained in and by the present Specification thereof, reference being had
to the Drawings hereunto annexed, that is to say:
Firstly, my Invention consists of an instrument for taking altitudes at sea or
on shore, which I call "The Universal Altimeter."
Figure 1 is a side elevation of this instrument. A is a broad ring of brass,
to one side (or the back of) which a telescope C is affixed in a horizontal or
diagonal line, exactly coinciding with the centre of the ring. B is a glass
tube of about a sixteenth of an inch in the bore, which is let into a groove.
made in the front of the ring, and extends all round with the exception of
about an inch or two, where a segmental air-tight junction piece F of metal
is inserted between the two ends of the tube which are left open, and com-
municate freely with the piece F. The tube is about half filled with mercury
(or other suitable fluid), which forms itself into a continuous thread of a
crescent shape, with a fixed quantity of air between the two cusps. As long
as the two fluids are left at liberty, they may of course be shifted round to any
parts of the circle, but in the middle of the junction piece F, there is a
valve V (not seen in the Drawing) inserted, which is worked by a spindle E,
and thumbpiece E, from the opposite side of the instrument, and when this
valve is closed, the motion of the fluids to either side of that valve is from that
moment necessarily stopped. The eye piece of the telescope is provided with
darkened glasses to save the eye from the glare of the sun, and the field of
view is divided in the centre by a wire to shew the line of collimation. On
the front of the brass ring A, immediately outside of the groove containing
the glass tube, and on opposite sides of the telescope, there are two quarter
circle scales R and L engraved. Both of these scales have their zero points
on the same line with the axial line of the telescope, but the numbers in R
run upwards from 0 to 90; while those in L run downwards from 0 to 90,
the 90°, in the one case R, representing the zenith, and in the other the nadir.
These scales are subdivided by two verniers D, D. The mode of using the
instrument is as follows:-The observer first releases the alcoholic, or other
fluid in the tube B, from the pressure of the columns of air at each end, by
turning the thumbpiece E¹ from left to right; he then directs the telescope
towards the sun or other object whose altitude it is desired to ascertain, and
brings the cross wire into contact (so to speak) therewith; which having done,

page_text: he turns the thumbpiece E¹ the reverse way, which fixes the mercury at the
exact level it had attained at the moment of contact, the column of air in B
pressing on the mercury at each end necessarily preventing the slightest dis-
placement. The observer next proceeds to read off the indications furnished
by the two scales of the instrument; he sets first down the numbers on the
left hand scale L, which come opposite to the top line of the fluid on the left
hand side, and then the numbers opposite the top line of the fluid on the
right hand side; which done, he adds the two sets of numbers together and
divides by two, which gives the required altitude.

page_text: time. He then sets the ring C to the same declination, turns round the
moveable quadrant or vernier D until it corresponds with the time, upon which
he raises the ring C to the true altitude, and, having fixed it there, turns the
quadrant or vernier round to 12 o'clock, and reads off the increased altitude
which gives the true meridian altitude. To find the apparent time in the
preceding operation, the observer should first take the latitude by account at
noon and set it to the meridian altitude, then reduce the declination to the
approximate time and take an altitude, next turn the quadrant round until the
altitude cuts the arc; when opposite thereto will be found the apparent time, as
also the sun's bearing.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that what I claim, as of my
Invention, is as follows:-
First, I claim "The Universal Altimeter" before described, that is to say,
in so far as regards the employment, for the purposes of said instrument, of
two fluids of different densities enclosed in a circular tube, or tube forming
some part of a circle, connected at the two ends by an air-tight segmental
junction piece, and the method of fixing these fluids at any required altitude,
independent of their natural gravity.
And second, I claim the instrument for finding the latitude and apparent
time at sea from the sun's altitude, before described, in so far as regards
the combination of the sliding ring C and vertical bars D, D, with the
other parts of the said instrument.
In witness whereof, I, the said Donald Beatson, have hereunto set
my hand and seal, this Tenth day of June, in the year of our Lord
One thousand eight hundred and fifty.