candle, 89, 139.

Precipitate of lead, 83, 85.

Precision, 7.

Pressure, 87.

Primary, 35, 62, 98, 134, 142, 159, 184.

Primary battery, 7, 99.

Primary circuit, 99.

Primary coil, 106, 109.

Prime conductor, 6.

Projected, 185.

Propagated, 105, 185.

Properties, 55.

Purification, 123, 128.

Purifier, 126, 131.

Push button, 65, 68, 69, 70, 76, 79.

Q

Quantity, 55, 60, 61, 138.

Quartz, 186.

R

Radio-activity, 186.

Radium, 184, 185, 187, 188.

Ratchet drill, 13.

Reaction, 148.

Receiver, 12, 90, 97, 121, 122.

Receiving station, 109.

Rectangular, 69.

Rectifiers, 146.

Red lead, 83, 84.

Reel, 13.

Reflected, 185.

Refraction, 185.

Refractory, 182.

Register, 57.

Removable, 54.

Removable cap, 73.

Repel, 20.

Repulsion, 21, 128.

Reservoir, 61, 62.

Resiliency, 99.

Resistance, 7, 36, 37, 60, 63, 99, 135, 136, 137, 138, 140, 141, 156,
157, 163, 166, 168.

Resistance bridge, 7.

Resistance, external, 37.

Resistance, internal, 37.

Rheostat, 7.

Reversed, 20, 50, 153.

Reversible, 163.

Reversing, 176.

Reversing switch, 67.

Revolubly, 46.

Revolve, 179.

Revolving, 177.

Roentgen rays, 184.

Roentgen tube, 187.

Rotation, 149.

Rubber, 40, 46, 77, 115, 126, 130, 138.

S

Sad-irons, 13.

Saline, 133.

Sanitation, 12.

Saturated, 85.

Screw, 15.

Screw, binding, 65, 66.

Screw-driver, 14.

Screw, set, 72.

Sealing wax, 53.

Secondary, 62, 98, 105, 158, 159, 160.

Secondary circuit, 99.

Secondary coil, 107, 108.

Self-induction, 149, 156.

Sender, 90, 97.

Sending apparatus, 106.

Sending key, 90.

Separately excited, 46.

Series-wound, 47.

Severed magnet, 20.

Sewage, 12.

Shaft, 30.

Shears, 14, 17.

Shellac, 40.

Shunt-wound, 47.

Signal, 118.

Silver, 19, 63, 125.

Silver nitrate, 62.

Socket, 54, 139.

Soldering, 14.

Soldering iron, 17.

Solution, 55, 57, 62, 63, 84, 86, 133, 134, 142.

Sounder, 90, 92, 95, 96.

Sounding board, 119.

Source, charging, 83.

South pole, 20, 21, 22, 25, 50, 54, 156.

Spark gap, 102, 106.

Spark jump, 99.

Spring finger, 69.

Square, 14, 17.

Standard, 62, 63.

Station, 94, 95, 117, 122.

Steel, 18, 19.

Steel magnet, 53.

Sterilized, 12.

Stirrup, 75.

Stock bit, 13.

Stock contact, 121.

Storage, 82.

Storage battery, 107.

Storing, 82.

Substances, 135.

Sulphate, 55, 128, 133.

Sulphur