This projectile, about which so much has been said, is of elongated form, and by a simple and ingenious combination of cast and wrought iron, secures all the advantages of the Minie ball. Being entirely of iron, it has a great superiority in an economical point of view over the various forms of leaded cannon balls that have been proposed, and possesses the important advantage of being used red hot when desired. The only change necessary to adapt it to the ordinary form of cannon, is f the cutting of two or three grooves in the gun. cK The invention insures an increase of range and X accuracy in the fire of artillery, also an in-pfcreased efficiency in direct shell firing.