A new composition has lately been invented by Messrs. Winiwarter and Gersheim, of Vienna, tor the purpose of superseding the ordinary percussion caps, and, in many instances, the gunpowder charge also. The most prominent feature of these gun primers, as the composition is called, are the absence of a metallic coat or cover, and their uniform explosive power, the materials being of such a nature that, after a .detonation, no residue whatever is left behind. The materials which form, the new composition are fulminating mercury, chlorate of potash, and sulphide of antimony, the dangerous properties of which ingredients are diminished by the application of collodion, which is used as a cement, and it is the ingenious employment of this substance which constitutes the chief peculiarity of the invention.