AN IMPROVED 'BACK SIGHT' FOR MILITARY RIFLES
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by Samuel Hill at the Office of the
Commissioners of Patents, with his Petition, on the 25th March
1875.
I, SAMUEL HILL, of Southwark, in the County of Surrey, do hereby
declare the nature of the said Invention for “AN IMPROVED 'BACK SIGHT'
FOR MILITARY RIFLES," to be as follows:-
This Invention relates to certain improvements in the "back sights"
of military rifles, and it has for a principal object the provision of
mechanical means, whereby in taking aim or sight at an object a due
allowance can be previously (or at the time) made for the effect exercised
upon the bullet or projectile by any wind which at the time of firing
may be blowing. With this provision a much surer aim can be taken
than as at present.
The improvements constituting the Invention consist in constructing
the flap of the back sight (which can be fitted to the rifle barrel in lieu
of and in the same manner as that of the ordinary back sight) much
wider than usual, so that at all ranges and at all times sight and aim
can be taken between its sides (as herein-after more particularly

page_text: described) direct at the object intended to be hit, whatever the force or
direction of the wind, and further, in fitting the flap with a scale and
traversing sighting bar actuated by means of a thumbscrew. This
sighting bar is made with a square sighting notch, and is marked with a
line of platina across it to render it the more conspicuous. The
divisioning of the scale depends altogether upon the particular variety
of military rifle to which the improved back sight is to be applied, that
is, upon the distance between its fore sight and back sight. With this
distance ascertained the divisioning is most easily computed. As an
example, in the "Snider" military rifle and in other varieties of military
rifles in which the sights are at a similar distance apart, the divisions or
degrees of the scale are marked at intervals of one-fortieth of an inch.
With this system of divisioning and in this rifle the firer can thus set
the sighting notch of the traversing rear sighting bar to 10 such degrees
either to the right or left of a direct line of sight along the barrel. It
will thus be seen that, as in all cases as a matter of course the firer as
hitherto takes aim by means of the adjustable rear sight and the usual
fore sight, this has the effect of pointing the barrel towards the one or
the other (the windward) side of the object aimed at or sighted through
the sights, and with which it necessarily is in line. In the Snider rifle
at a range of 800 yards (the flap is marked as ordinarily to attain the
necessary elevation), and with the rear traversing sighting bar and notch
moved to its utmost extent (the said 10 degrees) to (say) the left of the
line of barrel in taking aim or sight through or by means of the "sights'
the barrel would be pointed about 17 feet 6 inches to the left (or wind-
ward) side of the object aimed at. At the same range but with a light
wind blowing the rear traversing sighting bar and notch need only be
moved (say) one degree or any other necessary number of degrees,
depending upon the apparent force of the wind to allow for and correct
the effect exercised upon the bullet or projectile by the lessened force of
wind:
"