A NEW METHOD & APPARATUS FOR ASCERTAINING THE DISTANCE OF DISTANT OBJECTS
Year: 1861

page_text: PROVISIONAL SPECIFICATION left by William Browning at the Office
of the Commissioners of Patents, with his Petition, on the 1st May
1861.
I, WILLIAM BROWNING, of St. John Street, West Smithfield, in the County
of Middlesex, Oil Merchant, do hereby declare the nature of the said Inven-
tion for "A NEW METHOD & APPARATUS FOR ASCERTAINING THE DISTANCE OF
DISTANT OBJECTS," to be as follows:-
My Invention, which relates to means of determining the distance of distant
objects without actual measurement, or any approach towards the object,
consists of a quadrant, marked to indicate miles and yards, and other distances
used in combination with a given base line. When used for the purposes of
gunnery, which I believe to be the principal application, I take, say, forty
yards as the base line, and use a wire, chain, or other suitable measure to
determine that base; this measure of forty yards I adapt to the quadrant,
and I distend it as near as may be at right angles to the direction of the object
whose distance is to be determined, and fix it in that position. I then apply
the one radius of the quadrant to & parallel with this base line at one end,
and by the sights of the measuring limb sight, the object, if the base line be
exactly at right angles to the direction of the object, and it is distant, say, for
example, 80 yards, the angle subtended from the base line will be 67°, and
this result will be obtained if the quadrant be applied at each end of the base
line, but the quadrant instead of being marked by degrees, is marked to show
the distance in yards, feet, & inches. If the object is further distant, the

page_text: angle will of course be greater in proportion. Supposing the base line not to
be at right angles to the direction of the object, then the quadrant will indicate
a greater distance at one end of the base line than at the other, the mean of
which may be taken as the true distance, or the position of the base line may
bé altered until the angles and distances indicated are alike. For greater or
lesser distances I use a longer or shorter base line and measure, and adapt
graduations on the quadrant thereto, and use it in a similar manner. I find it
advantageous to use two quadrants, & dispose one at fifty yards distant from
the other, and then sight them by sights on distended arms to adjust their
positions true with each other. I then read off the distances indicated by the
quadrant sights, by which the augles are taken from the object whose distance
is to be determined, and if the readings are the same the base line will be at
right angles to the line of the distant object, and if not, the mean of the distanco
indicated may be taken, or the quadrants readjusted until the base is in
correct position. Instead of ascertaining the distance by equal angles &
measures determined at each end of the base line, the one angle at the end of
the base line may be a right angle in all cases, and the distance read off from
the quadrant at the other end of base line. For this purpose I use a telescope
or other suitable sighting apparatus, which I point at the distant object; on
this telescope or sighting apparatus I apply a cross sight at right angles
thereto, and from it measure a distance of, say, forty yards in a direct line at
right angles to the telescope, and in line with such cross sights. At the
distance of forty yards I place the quadrant, and sight the zero radius thereof
in line with cross sight of the telescope, and then sight the object by the
telescope or sights of the measuring limb of the quadrant for determining the
angle formed with the base line at that point, the quadrant being suitably.
marked and graduated, will show the distance of the object, which distance can
be at once read off.