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MINUTES OF PROCEEDINGS OF 
With rifled guns smaller charges must be used, because elongated projectiles in 
addition to the motion of translation are forced to take a motion of revolution due 
to the twist of the grooves; this is only feasible when the impulse of the force of 
the powder which sets the projectile in motion does not exceed a certain limit. If 
the charge of powder, an^ consequently the impulse in the direction of the motion 
of translation to which the projectile is subjected, be excessive, the projectile 
has not sufficient time to follow the twist of the grooves; the guiding surfaces of 
the projectile are stripped, and the desired rotation round the longer axis does not 
take place. 
As, further, the elongated projectiles of rifled guns are considerably heavier than 
spherical projectiles of the same diameter; if we wished to use as high charges as 
with smooth-bores, we should be compelled to increase the thickness and weight 
of rifled guns and their carriages, to enable the gun to stand the increase of work. 
(2) The loss of velocity sustained by the projectile in its flight, consequent on 
the resistance of the air, is much less with elongated than with spherical projectiles; 
this result is due to the form of the former being better suited to overcoming the 
resistance of the air and to its mass being greater than that of the spherical projectile 
of the same diameter. The remaining velocities of elongated projectiles are conse¬ 
quently greater than those of spherical projectiles; the difference increasing with 
range. In consequence of the smaller loss of velocity, the trajectories of elongated 
projectiles at long ranges are flatter and effectively command more ground than 
those of round shot. 
(3) It is well known, that the round shot of the smooth-bore gun during its 
passage down the bore bounds against the sides of the piece; that, due to the 
windage and the position of the varying centre of gravity, the shot leaves the bore 
rotating round a variable axis; and that, as the result of these circumstances, the 
regularity of the trajectories is materially and prejudicially affected. In the 
Austrian system of rifled guns, pattern 1863, the projectile is centred in loading 
(Eig. 6); it is forced by the grooves to retain that position while in motion inside 
the bore and simultaneously to assume a motion of rotation from left to right about 
its longer axis. Despite the windage of guns on this system, bounding of the 
projectile in the bore cannot occur as the bearing of the projectile is symmetrical. 
Hence the angle of departure is invariable; this circumstance in combination with 
rotation on a constant axis and in the same direction, essentially contributes to the 
regularity of the trajectory. 
(4) The trajectories of spherical projectiles diverge to the right or left of the 
vertical plane through the axis of the piece, from the variation of the angle of 
departure and of the direction of rotation; those of elongated projectiles rotating 
to the right form a curve regularly diverging to the right of that plane. 
(5) The ricochet of elongated projectiles is less regular than that of round 
shot; for the elongated projectile after the first graze varies in its position with 
reference to the resistance of the air; whilst the round shot invariably opposes a 
similar figure to that resistance. 
Laying. 
16. Laying a rifled gun (generally done before loading) involves two 
operations; giving the piece the required elevation or depression, and 
making the allowance for drift. 
The object of elevating or depressing the gun is to give its axis a definite 
inclination to the horizon, thereby regulating the range to the distance of 
the object. 
