420 REPORT— 18GG. 



OG tons per inch of shot's circumference, penetrated completely, and were fully 

 equal to the steel. 



4tli. That elHptical or blunt-headed chilled shot, striking the above target 

 •with a " work " of 06 tons per inch of shot's circumference, failed to pene- 

 trate completely, the indent being about equal to that made by the hemi- 

 spherical-headed steel shot. 



5th. That ogival -pointed chilled shot striking the 4-5-inch unbacked 

 plates, inclined at angle of 38° with the ground, with a " work " of GO 

 tons per inch of shot's circumference, penetrated completely. 



Gth. That the same shot with the Belgian coned head failed to jieuetrato. 



7th. That it would reqiiire a " work " of above 70 tons per inch of shot's 

 circiimference to send a hemispherical-headed steel shot completely through 

 4-5-inch unbacked wrought-iron plates, inclined at an angle of 38° with 

 the ground. Such a structure therefore presents a greater obstacle to com- 

 plete perforation than the ' Warrior ' target if fired at chrect. 



Sufficient experiments have not yet been made with pointed shot to 

 enable us to determine the value of Ic for this form of projectile with any 

 great exactness. 



It is probable, however, that Ic for pointed shot will be found to be about 

 four-fifths of that for hemispherical-headed projectiles, when the target is 

 backed, or 



I' = A 5357200, 

 Z.' = 42857G0. 



Spherical versus Elongated Projectiles, 



The experiments against iron-plated targets have clearly demonstrated 

 the immense sui^eriority of elongated over spherical projectiles, when the 

 shot or shell are made of a hardened material. Elongated projectiles have 

 been found to be less liable to alter their shape on impact ; and the c^din- 

 drical form is much better adapted for steel shells, which as spherical woidd 

 be almost worthless. The best form of steel shell known at present is the steel 

 solid-headed shell, the head being ogival and moveable, so as to offer th 



e 



least resistance to the action of the bursting charge in the forward direction. 



The chief characteristics of this projectile are : — its solid pointed head, 

 which penetrates or punches a hole in the armour, and so permits the 

 powder to explode in the backing*; and the construction of the head 

 which renders it very strong when acted on by a force from the outside, 

 but weak when subject to pressure from within ; it is thus easy for the 

 bursting charge to blow the head forward through the backing and inner skin. 



The form of this projectile is also well adapted for the use of gun-cotton 

 as a bursting charge, the cotton being made up in the improved manner, 

 viz. disks of pulp. These shells having been first proposed by Cajitain H. 

 J. Anderson, ll.A., are known as the " Alderson shell; " and Table XIII. (in 

 the Appendix) shows what success attended their use (rounds 1048-1050). 



It is believed that Sir William Armstrong was the first to point out the 

 advantage to be gained by causing the powder to act in a forward direction ; 

 and the steel shells known as the " Armstrong pattern " are thus made. 

 All these shells, however, are furnished with hollow east-iron heads or caps, 

 and their penetration is inferior to the shells with solid steel heads. 



* See R. A. luatitution Proceedings, vol, iii. page 71) line 21. 



