IMPROVEMENTS IN THE CONSTRUCTION OF MITRAIL- LEURS OR MACHINE GUNS
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Henry Heather Bigg at the
Office of the Commissioners of Patents, with his Petition, on the
28th November 1870.
I, HENRY HEATHER BIGG, of Wimpole Street, Cavendish Square, in
the County of Middlesex, Civil Engineer, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF MITRAIL-
LEURS OR MACHINE GUNS," to be as follows:-
My Invention of improvements in the construction of mitrailleurs
or machine guns has for its object to increase the efficiency of these
warlike implements by imparting lateral movements to the barrel so that
a variable fan-like direction may be given to their fire.
To this end instead of combining all the barrels together as in the
Gatling gun or the French or Belgian mitrailleuses, I divide the
number of barrels into three sets, in each of which the barrels may be
arranged in a circular bundle, or if preferred in a line or lines. Of the
three sets or series of barrels the central one will not require any lateral
motion or adjustment, but need only be capable of elevation or depression
like ordinary field pieces. The other two sets of barrels must be capable

page_text: of lateral motion (on a vertical centre) to the right and left as well
as of elevation and depression. This lateral motion is given by means
of a right and left-handed screw working in screw nuts attached to
the barrels, and motion is communicated to this screw by means of a
hand wheel provided with any convenient number of handles, levers,
or spokes of different lengths corresponding to the amount of divergence
required to be given to the barrels, and consequently to the storm of
projectiles delivered by the gun. For instance, it may be arranged
that the largest handle when brought to a given position will turn the
lateral adjusting screw to such an extent as to deliver at 1,500 yards
a storm of bullets extending laterally for, say, 60 feet. If it be desired to
reduce the range without reducing the lateral spread, then upon bringing
the second handle into the position before occupied by the first, the
barrels will be spread out to such an extent as will cause the bullets at
a range of, say, 1,000 yards, to be extended over the same lateral area
as at 1,500, viz., 60 feet. Upon bringing round the third handle the
bullets will be delivered over the 60 feet, at 500 yards, and so on,
gradually increasing the lateral spread of the projectiles as the range is
reduced. In this way the dispersion of the projectiles may be increased
or decreased at pleasure in accordance with the orders of the com-
manding officer. The object of adapting to the lateral adjusting screw,
(whereby this dispersion is controlled), a wheel with spokes of unequal
lengths is that the gunner may be able to give the required amount of
dispersion without the necessity of examining any index, which it might
be difficult to do owing to the smoke. The three sets of barrels may
be capable of elevation or depression separately so that when firing at
troops ranged on the side of a hill at different elevations the gun may
be adjusted accordingly.