LIST OF ILLUSTRATIONS

Fig.		Page
1	Electric bell, push, and battery	[x]
2	Leclanche cell	[1]
3	Dry cell	[4]
4	Gravity cell	[5]
5	Vibrating bell	[10]
6	Single stroke bell	[10]
7	Shunt or short circuit bell	[10]
8	Continuous ring bell	[13]
9	Waterproof bell	[14]
10	Dome gong	[15]
11	Tea gong	[15]
12	Cow gong	[15]
13	Sleigh bell gong	[15]
14	Spiral gong	[15]
15	Relay and circuit	[16]
16	Door push	[19]
17	Pear push	[19]
18	Door push	[19]
19	Wall push	[19]
20	Floor push	[20]
21	Door pull attachment	[22]
22	Wire joint first operation	[25]
23	Wire joint second operation	[25]
24	Wire joint insulating	[25]
25	Section of house showing wiring	[29]
26	Bell with ground return	[30]
27	Pushes in multiple	[31]
28	Bells in series	[31]
29	Bells in multiple	[31]
30	Two bells and two pushes	[32]
31	Two bells and two pushes	[32]
32	Two bells, two pushes and one battery	[33]
33	Double contact push	[33]
34	Grounded bell	[34]
35	Tongue test of wiring	[38]
36	Knife test of wiring	[38]
37	Knife test of wiring	[39]
38	Metallic thermostat	[40]
39	Mercury thermostat	[41]
40	Mercury thermostat circuit	[42]
41	Water level alarm	[44]
42	Lever water level alarm	[45]
43	High or low water level alarm	[45]
44	Window spring for burglar alarm	[47]
45	Burglar alarm—closed circuit	[47]
46	Special bell connection for burglar alarm	[48]
47	Special bell connection for burglar alarm	[49]
48	Burglar alarm and relay	[50]
49	Window-shade contact spring	[51]
50	House wired for burglar alarm	[52]
51	Door trip alarm	[53]
52	Annunciator drop	[55]
53	Needle drop	[56]
54	Needle drop indicating	[56]
55	Pendulum drop	[57]
56	Annunciator drop circuit	[58]
57	Simple annunciator circuit	[59]
58	Annunciator and fire call circuit	[60]
59	Single-wire room and fire call	[61]
60	Three-wire return call circuit	[65]
61	Elevator bells and annunciator circuit	[67]
62	Burglar alarm annunciator circuit	[69]
63	Clock alarm circuit	[71]
64	Bell-ringing transformer	[73]
65	Bell-ringing transformer with three secondary voltages	[73]
66	Western Electric interphone system	[75]
67	Western Electric interphone system for more extensive service	[77]
68	Fire alarm circuit	[79]
69	Interior fire alarm circuit	[81]
70	Fire alarm circuit for considerable areas	[82]