1892.] 



by Friction in the Bores of Rifled Guns. 



411 



quick-firing guns were specially prepared and rifled in the following 

 manner : The first had grooves of the usual section of the Service, 

 but these grooves were all cut parallel to the axis of the bore, that is 

 to say, the pitch of the rifling was infinite, or, iu other words, there 

 was no twist, and no rotation round the central axis would be com- 

 municated to the projectile ; the second gun was rifled with a 

 uniform pitch of 1 turn in 162 inches (about 1 turn in 35 calibres) ; 

 while the third gun was rifled with a uniformly -increasing pitch of 

 from 1 turn in 472" '5 at the breech to 1 turn in 162" at the muzzle, 

 so that in the last two guns, assuming the same muzzle velocity, the 

 projectiles would leave the gun with the same angular velocity. 



The projectiles used in these experiments were flat-headed cylin- 

 ders (all being made of the exact weight of 45 Ibs.), and differed from 

 one another solely in the driving bands of the projectiles, which 

 differed from one another both in diameter and length, the differences 

 being shown in the sketches attached to the tabular results. 



The first experiments were made with the lings marked " A," 

 three rounds being fired from each of the three guns described, and 

 the following table shows the velocities and energies obtained frcra 

 each nature of gun. 



Table 1. Results of Experiments with Driving Rings 

 Section u A." 



