48 Laboratory Arts 



Note. Where soldering is to be made use of, the wires should 

 be cleaned with emery-paper before twisting, and they should not 

 be touched with the fingers more than is absolutely necessary. 



Wherever the wires are to be used for electrical purposes, resin 

 should be used as a flux, in place of zinc chloride, as this latter 

 necessitates washing the work in hot water, and this is not 

 permissible in electrical work. 



Method i. Two wires having both ends free. Place the wires 

 so that they overlap at right angles, as shown in Fig. 38. Place 

 the thumb and forefinger of each hand at the intersection, and 



move each hand in opposite 

 directions, twisting evenly. 

 The commencing point will 

 not be visible if this is cor- 

 rectly done, and the wires will 

 be evenly twisted throughout 

 the joint. 



Method 2. Two wires long 

 enough to overlap, but with 

 FIG. 38. one end of each fixed. 



Grasp the wires at the centre of the overlap with pliers, and coil 

 one free end round the other wire in close coils (see Fig. 39). When 

 this is done, move the nose of the pliers till it grasps the first 



coil, and repeat with the second 

 free end. The centre will be 

 slightly different from the rest 

 of the coil, but will be sufficiently 

 strong. An alternative method 



is to place the wires to be joined 

 finished j i 'j -i 



side by side, and to wind round 



these, in close coils, a third wire, 

 Commencing to wind in the 

 FIG. 39. middle of the overlap and the 



centre of the third wire, gripping meanwhile with square-nosed 

 pliers. The ends of the original wires should finally be turned 

 up, and cut off short with cutting pliers. 



Method 3. Two wires as above, but too stout for coiling. 

 Clean each wire, and file the ends in a plane, cutting the axis of 

 the wire at an acute angle (see Fig. 40). Place these together, face 

 to face, and bind with thin (No. 32) wire in a close coil. This is 

 best done by laying one piece of the No. 32 wire along the joint, 

 and wrapping it back upon itself, when the two ends are available 

 for "fastening off" by twisting. 



