Whit worth Projectile

—The cro -section of the bore of the Whit worth gun is a hexagon with the corners slightly rounded. The projectile is first formed so that its cro -section is a circle, and its sides taper towards both ends. The middle portion is then carefully planed off to fit the bore of the gun. The Whit worth blind shell for firing against armor-plates, is made of tempered steel, and each end is closed with a screw. To prevent the heat of impact from acting too soon on the bursting charge, it is surrounded by one or more thickne es of flannel. A 7-inch shell of this kind has been found to have sufficient strength and stiffne to penetrate 5 inches of wrought iron before bursting.