rENliXKATION Ol' IKOX I'LATliS BV STKDL .SHOT. 



105 



Determmation of the cJiarges. — The charges were determined with the aid 

 of Ifavez's apparatus, by whicli the velocitj- of each projectile was observed 

 at the distance of 100 yards from the muzzle. Cast-iron shot were sup- 

 plied for this experiment, their weight being the same as the steel shot. 

 The spherical projectiles were shells weighted up with lead. 



The following Table shows the velocity which it was necessary each pro- 

 jectile should have in order that the conditions might be fulfilled : 



TAiJlE I. 

 perimc 

 shot 



— ShoAvdug the necessary velocities and charges determined by ex 

 nt. 5-5-iuch plates. Projectile, solid steel hcmispherical-headei 



The necessary charges ha\T.ng been thus previously ascertained, the guns 

 were placed in battery at 100 yards from a row of 5|-inch iron plates firmly 

 fixed by upright supports, but unbacked f. 



The actual velocity of each round was observed at a short distance in front 

 of the plate, and the striking- velocity determined by calculation. 



The following Table (p. 406) gives the results. 



It appears that the striking-velocities of the steel shot varied slightly from 

 those pre-viously determined and detailed in Table I. above. This shght 

 difference is due to minute variations in the weights and diameters of the 

 projectiles, and atmospheric influences, errors which it is quite impossible to 

 guard against. Such differences, however, are of no practical importance 

 whatever. 



* Previous experiments had been made with these gmis. 



t The guns were fired directly at tlie plates ; that is to sav, tlie plane in which the shot 

 moved was perpendicular to the face of the plates. 



