Popular Science Monthly 



789 



W 



the brass ferrules around the hole (Fig. 

 i), apply a small amount of solder to 

 each. Assemble the fuse by slipping 

 the copper wire through the hole; then 

 apply solder and mend with a hot iron. 

 Fit the fuse in the fiber and in the hole 

 in the opposite brass ferrule. Tin in the 

 same way as before and cut the copper 

 wires flush with the brass end, as in 

 Fig. 2. The fuse will then be found to 

 be as serviceable as before. 



Substituting a Flashlight for a Door- Bell 



'HEN there is 

 sickness in 

 the house, it is 

 often necessary to 

 avoid all noise as 

 far as possible. At 

 such times the door- 

 bell is a source 

 of great annoyance. 

 To overcome this 

 difficulty, disconnect the wires from 

 the bell and run them down the gas 

 or electric fixtures. Leave the ends 

 bare and bend them into hooks, as 

 shown in the diagram. Secure a flash- 

 light bulb and solder two wires to it, 

 bent as shown. The flashlight can then 

 be connected with the push-button at 

 the door by simply hooking it on to the 

 wires. 



This arrangement is also of great 

 service to anyone who is deaf. If wires 

 are arranged in every room, the flash- 

 light can be attached in whichever room 

 the deaf person happens to be. Thus a 

 bell is not needed. — J. K. Noble. 



Telephone-Line Test- Clips Easily Made 



NY telephone 



A' 



man can make 

 a pair of line test- 

 clips for ten cents. 

 F?uy two large 

 safety-pins and cut 

 j^ in. off the point 

 of each. Solder a 

 piece of No. 6 cop- 

 per wire, i3^ ins. 

 long to the part 

 from which the 

 {)oint was cut so 



that it will pass between the wires at 



the open end of the pin. 



File a small groove in the copper in 



which the line wire may rest. Then 

 simply solder the test cord to the loop at 

 the other end of the pin. 



Changing a Telegraph Sounder 

 Into a Relay 



A TELEGRAPH 

 sounder can 

 easily be changed 

 into a relay by add- 

 ing a small piece of 

 copper as shown in 

 the accompanying 

 diagram. A piece 

 of sheet copper is 

 bent as shown and 

 placed under the 

 screw C, but previous to this, a piece 

 of thin mica is placed between screw C 

 and stand E at D. A piece of small 

 wire is coiled and carried from the 

 screw B to the screw C, to insure a 

 good contact. 



The two telegraph wires are attached 

 to the regular binding posts and the; 

 relay wires are connected with screw B 

 and copper A. When the magnet's base 

 is drawn down, the arm F completes, 

 the circuit in B and A. — Wm. Harrier. 



A Current Reverser for Small Motors 



A DOUBLE-POLE, double -throw 

 switch, if connected according to 

 the accompanying diagram, will reverse 

 the direction of a direct-current motor. 

 Disconnect the wires on the motor that 

 are connected to the binding posts, 

 brushes and field. Connect binding 

 post No. I of the switch and No. 6 post 

 to one end of the field. Connect the 

 other field terminal to posts No. 2. and 

 No. 5. One brush is connected to one 

 binding post of the motor and No. 3 

 post of the switch. The other brush is 

 connected to No. 4 post. The batteries 

 are inserted between one of the binding 

 posts on the motor and No. 3 post of 

 the switch. 



Diagram of current reverser for small motors 



