430 REPORT— 1869. 



be uniformly distributed over the area of one, but would be borne in a 

 larger proportion by the outside particles, where they join the increased 

 section. 



It will not be necessary to go into the reconsideration, in respect of trans- 

 verse strains, of the effects of inertia and vibration, which have already been 

 touched on when considering direct strains ; but it wiU be suiRcient to say 

 that the strains brought upon railway axles are of a very severe character, 

 and that they are undoubtedly exaggerated by the large difference of dimen- 

 sions of the neighbouring parts, and that nothing but the greatest circum- 

 spection in the designing and manufacture of these parts can insure safety 

 to railway passengers. 



On the Penetration of Armour-plates with long Shells of large capa- 

 city fired obliquely. By Sir Joseph Whitworth, Bart., C.E., 

 F.R.'S., LL.D., D.C.L. 



At the Meeting of the British Association at J^orwich, I contributed a paper to 

 the Mechanical Section " On the Proper Form of Projectiles for Penetration 

 through Water." This paper was illustrated by diagrams, showing the effect 

 produced on an iron plate, immersed in a tank of water, by projectiles with 

 Hat, hemispherical, and pointed heads. Copies of those diagrams are now 

 before you. In that paper I claimed for the flat-pointed fomi of projectile, 

 made of any metal, three points of superiority over the ogival-pointed pro- 

 jectiles adopted in the ser'^ice : — (1) Its power of penetrating armour-plates, 

 even when striking at extreme angles ; (2) its large internal capacity for 

 bursting charges when constructed as a shell ; (3) its capability of passing 

 undeflected through water, and of penetrating iron armour below the water 

 line. This latter feature was, I think, satisfactorily proved by the experiments 

 described last year; and I desire to draw the attention of the Section^ to 

 the experiments I have made for illustrating the penetrative power of long 

 projectiles with the flat front, fired at extreme angles against iron plates. 



These experiments are illustrated by the projectiles actually fired, and the 

 plates they penetrated, which are laid on the table, and also by the diagrams 

 before you. 



The gun from Avhich the projectiles were fired is called a 3-pounder, though 

 capable of firing much heavier projectiles. It weighs 315 lbs., and the maxi- 

 mum diameter of its bore is 1-85 inch. The charge of powder used, in all 

 cases, was 10 ounces, and the weight of the 6-diameter projectile is 6 lbs. 



No. 1 is a portion of a plate 2 inches thick, penetrated by the 6-diameter 

 flat-fronted projectile No. 1 at an angle of 35 degrees. No. 2 is a similar 

 piece of plate, 1-7 inch thick, completely traversed at an angle of 45 degrees 

 by the flat-fronted projectile No. 2, which buried itself to a depth of 30 inches 

 in a backing of iron borings. No. 3 is a piece of plate 1-75 inch thick, pene- 

 trated at an angle of 65 degrees by the flat-pointed projectile No. 3. No. 4 

 is a plate 1-7 inch thick, nearly penetrated, at an angle of 45 degrees by the 

 3^-diameters flat-fronted projectile No. 4. No. 5 is a plate 1| inch thick,, 

 against which the ogival-pointed projectile No. 5 was fired at angle of 45 

 degi-ees ; the projectile failed to penetrate the plate, being deflected in con- 

 sequence of the ])ointed form of the head. The distortion of its shape shows- 

 the force with which it stnick the plate, and proves the good quality of the- 

 material which could resist such a test. No. 6 is a plate also 1^ inch thick, 



