_Beardslee's Fuze._--This high tension fuze is shown at Fig. 27. It consists of a cylindrical piece of soft wood a, which is about three-quarters of an inch in length and in diameter; two copper nails, _b_, _b_, are driven through this piece of wood _a_, in such a way that while the two heads come together as close as possible without absolutely touching, the pointed ends are some distance apart from each other, and project through the wood _a_; two insulated copper wires, _c_, _c_, are firmly soldered to these projecting ends, and a piece of soft wax, _d_, is pressed around the junction points. In a groove, across the heads of the copper nails, is placed a little black lead, to which is added a minute quantity of some substance, the nature of which is known only to Mr. Beardslee. Several folds of paper are wrapped round the wooden cylinder, forming a cylinder about 2-1/2 inches long, one end of which is tightly fastened round the insulated wires as at _e_. The other end of the cylinder is then filled with powder, _f_, and closed by a piece of twine. The whole fuze is then coated with black varnish. Though not highly sensitive, Beardslee's fuze is exceedingly efficient, and extremely simple. _Von Ebner's Fuze._--This form of fuze was devised by Colonel Von Ebner of the Austrian Engineers. A section and elevation of it is shown at Fig. 28. It consists of an outer cylinder, _a_, of gutta percha, and an inner one of copper, _b_, which latter encloses a core formed of ground glass and sulphur, _c_, which core is cast round the two conducting wires _d_, _d_ in such a way that they are completely insulated from one another. In the first instance the wire is in one continuous length, the opening _e_ being subsequently made, and carefully gauged, so as to ensure a uniform break, or interval in the conductor of each fuze. The priming composition, which consists of equal parts of sulphide of antimony and chlorate of potash, is placed in the hollow _f_, to which is added some powdered plumbago, for the purpose of increasing the conducting power of the composition. This mixture is put into the hollow, _f_, of the fuze under considerable pressure, the terminals being connected with a sensitive galvanometer, in circuit with a test battery, and the pressure applied so as to obtain, as far as possible, uniformity in the electrical resistance of each fuze. The Austrians employed this form of high tension fuze in connection with a frictional machine for the electrical mines used in their defence of Venice, &c. during the war of 1866. _Abel's Fuze._--Mr. Abel devised a high tension fuze, which in 1858 was extensively experimented with; the Beardslee and Von Ebner fuze being based upon the principles applied for the first time in Abel's fuze. [Illustration: ELECTRICAL FUZES. PLATE VII]