_McEvoy's Joint for Iron Wire covered Cable_.--This form of joint is shown in section at Fig. 39. Two brass caps _a_, _a_ are slipped over the ends of the cables required to be joined, then the iron wire and other coverings of the cables down to the insulating substance are removed, the former being bent back close against the bottom of the caps _a_, _a_, as shown in Fig. 39 at _b_, _b_; the cores of the cables are then joined by an india rubber temporary joint _c_, which has been described at page 45: the whole is then placed in the body of the joint, and the brass caps _a_, _a_ screwed up, jamming the bent back iron wires against a solid piece of brass _d_, _d_, by which means a firm and perfect joint is made in the cables. [Illustration: PERMANENT JOINTS FOR ELECTRIC CABLES. PLATE IX] Fig. 40 represents a section of a McEvoy temporary joint for single cored unarmoured cables, which seems to fulfil all the conditions necessary to a perfect joint of that description. This joint is, with the exception of there being two screw plugs instead of one, very similar to Beardslee's joint described at page 46; this alteration is a great improvement, remedying as it does the one defect of Beardslee's joint, viz., the liability of the cables to be drawn apart due to any great tension being brought on them. A permanent joint in electrical submarine cables, which from its nature requires to be an exceptionally good one, is a somewhat difficult and troublesome operation, and also requires a considerable time to form a thoroughly reliable one. _Siemens's Methods of Jointing._--The following methods, and instructions for forming such joints, are those adopted by Messrs. Siemens Brothers in connection with their telegraph cables, and which will be found generally applicable to all insulated cables. _The Formation of a Joint in the Conductor of an Insulated Cable._--The conductor is either covered with a gutta percha or an india rubber dielectric. In both cases cut off the dielectric so as to bare the conductor-wire for a length of about three inches, taking care never to cut at right angles to the conductor-wire, for fear of injuring it with the cutting-knife or scissors. Then clean the wires forming the strand with file-card and emery-paper, and solder them into a solid bar for a length of about one inch. Having soldered the wires, forming the ends of the two lengths of conductors to be joined, into two solid rods, file each of them off in a slanting manner, so that they will form a scarf-joint when put together. Place the two ends of strand in the two small vices on a stand which is supplied for the purpose, so that the two scarfed ends overlap each other, and bind them round with a piece of fine black iron wire, in the shape of a spiral, so as to keep the ends close together, then solder the two ends together by applying a hot soldering iron. Then remove the iron binding wire and clean up the joint, filing off all unnecessary solder.