IMPROVEMENTS IN CANNON AND MORTARS, AND IN PROJECTILES FOR THE SAME
Year: 1861

page_text: PROVISIONAL SPECIFICATION left by Giovanni Franci at the Office of
the Commissioners of Patents, with his Petition, on the 12th January
1861.
I, GIOVANNI FRANCI, of 29, Boulevart St. Martin, Paris, France, Proprietor,.
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN CANNON
AND MORTARS, AND IN PROJECTILES FOR THE SAME," to be as follows:-
My Invention relates to what I term 'a "mortar cannon," from the capa-
bility of using it either as a mortar or a cannon. When intended to be used as
a cannon the mortar serves as a breech for the chamber of the gun, properly
so called, and is solidly connected to it by a double hinged piece or other
mechanical equivalents allowing of its being easily connected or disconnected.
The tube or guiding body of the gun has lateral openings running nearly its
whole length, and is formed of several cylinders or rings, on which are cast or
forged longitudinal ribs or parts serving to connect the said rings. This
open tube is grooved or rifled on a certain number of ribs projecting internally
of an angular or prismatic shape. This tube may also be lengthened when
required by additional portions having similar lateral openings to the fore-
going which abut end to end, and are connected by screws, keys, bolts, or
otherwise.
Instead of lengthening the tube of the cannon it may be shortened
by dismounting one or more of the parts of which it is composed. The
chamber of the mortar is formed of two cylindrical bores, the one of greater

page_text: depth & smaller diameter than the other in which the charge of powder is
fired by the percussion, and the other of less depth but of greater diameter
serving to lodge the ball, the base of which is hollowed out and rests on
the metal resulting from the difference of diameter of the two bores.
The body of the mortar, properly so called, formed by the larger bore, is
like that of the cannon grooved or rifled internally with a number of pro-
jections of angular or prismatic shape, on which the ball is forced to fit, as
afterwards described. The mortar may be lengthened at will by means of
open tubes with projections for rifling, and similar to the tube of the cannon
but shorter, and which may be connected to the mortar by keys, pins, screws,
or preferably by hinges. This tube is added when using the mortar simply for
directing the flight of the shell and increasing its range.
The distinctive characteristics of the bullet or projectile are as follows:-
It is of a lengthened form, terminated hemispherically at one end, and at the
other by a flat surface resting on the surface of metal produced by the
difference of diameter of the two bores or chambers, and also on the charge of
powder in the smaller chamber. The projectile has also straight hollow
triangular grooves, in which fit the rifling or projections before described of a
similar section to either the cannon, mortar, or additional lengthening pieces,
these grooves are furnished with a coating of lead, for the purpose of pre-
venting windage in the close part of the bore after the explosion.
The cannon and mortar may be mounted on the same or separate carriages
and are furnished with all the ordinary appurtenances necessary for their use.