Now the dynamos may generate a current of 220 volts, and send it, at this strength, through the outer wires; but if lamps are connected between either of the outer and the neutral wires, the current, passing through the lamps, will be reduced to 110 volts.
Time-ball, Electric. A ball which, by means of electricity, is made to drop from the top of a high pole, giving a visual signal for twelve o’clock or any other hour that may be designated.
Traction, Electric. The propulsion of a car or conveyance by means of electricity.
Transformer. In alternating-current systems, the induction-coil by means of which the primary current, with high initial electro-motive force, is changed into a secondary current with low initial electro-motive force.
Transmission. The conveyance of electric energy and currents from one point to another by the proper means of conduction.
Transmitter. An instrument which originates the signals which are sent through a line or circuit. The Morse key in telegraphy and the Blake transmitter in telephony are examples.
Tri-phase. Three-phase.
Trolley. A contact-wheel of bronze which rolls under the supply-wire in an overhead traction system and takes off the current necessary to run the car motors.
Trolley-wheel. The same as Trolley.
Trolley-wire. The overhead wire in a traction system which feeds the current through a trolley-wheel and pole to the motors of a car running underneath.
True Ohm. (See Ohm, True.)
True Resistance. (See Resistance, True.)
Two-wire Circuit. The single system universally used for light and power transmission of current.
U
Undulating Current. (See Current, Undulating.)
Uniform Magnetic Field. (See Magnetic Field, Uniform.)
Unipolar. Having but one pole.
Unit. The single standard of force, light, heat, magnetism, attraction, repulsion, resistance, etc.
V
Vacuum. A space empty or void of all matter; a space from which all gases have been exhausted.
Vacuum Tubes. Tubes of glass through which electric discharges are passed after the gases have been partially removed; for example, the X-ray tube of Röntgen and the Crooke tubes.
Vibrator, Electro-magnetic. The make-and-break mechanism used on induction-coils, or other similar apparatus, in which, through alternate attractions, an arm or spring is kept in motion.
Vitriol, Blue. A trade name for copper sulphate. (Bluestone.)
Vitriol, Green. A trade name for ferrous sulphate. (Copperas.)
Vitriol, White. A trade name for zinc sulphate. (Salts of zinc.)
Volt. The practical unit of electro-motive force; the volume and pressure of an electric current.
Voltage. Electric-motive force expressed in volts—as, a voltage of 100 volts.
Voltaic. A term derived from the name of the Italian scientist Volta, and used in many ways as applied to electrical current and devices. Formerly the term galvanic was commonly employed.
Voltaic Electricity. (See Electricity, Voltaic.)
Voltimeter. An instrument for measuring the voltage of a current.
Vulcanite. Vulcanized rubber. Valuable for its insulating properties and inductive capability.
W
Watt. The practical unit of electrical activity; the rate of work or rate of energy. It is a unit of energy or of work represented by a current of one ampere urged on by one volt of electro-motive force.
The volt-ampere.
The standard of electrical energy corresponding to horse-power in mechanics.
Watt-hour. A unit of electric energy or work; one watt exerted or expended through one hour.
Waves, Electro-magnetic. Ether waves caused by electro-magnetic disturbances affecting the luminiferous ether.
Welding, Electric. Welding by the use of the electric current.
Wimshurst Electric Machine. An influence machine for producing high potential or static electricity. Thin disks of glass are mounted on insulated bearings and revolved by power. Brushes collect the frictional electricity, which is discharged into a Leyden-jar or other form of accumulator. It is of no practical use excepting in electro-therapeutics.
Wire, Flexible. A cord of fine wire strands laid together and insulated so that it may be easily bent or wrapped.
Wiring. Installing wires so as to form a circuit for the conveyance of current for light, heat, and power.
X
X-rays. A curious phenomenon involving the radiation of invisible rays of light, which have the power to travel through various opaque bodies. The rays are used in detecting foreign substances in the human body and for photographing invisible or hidden objects without disturbing their surroundings.
X-ray Lamp. A high vacuum tube lamp whose interior walls are covered with crystals of calcium or other fluorescent substances, and which, when exposed to the X-rays, give out a luminous light.
Y
Yoke. A piece of soft iron which connects the ends of two portions of a core on which wire coils are wound. It is located at the ends farthest from the poles.
The soft-iron bar placed across the ends of a horseshoe magnet to retain its magnetism.
Z
Zinc-battery. A battery which decomposes zinc in an electrolyte, thereby producing a current.
Zinc Currents. Negative currents.
Zinc-plating. The employment of zinc in electro-plating.
THE END
Transcriber’s Notes
Inconsistent spelling, hyphenation, etc. have been retained, unless mentioned under Changes Made below. Technical descriptions have been kept as printed, even when they seem doubtful, wrong or dangerous.
Depending on the hard- and software and their settings used to read this text, not all elements may display as intended.
Changes Made
Footnotes and illustrations have been moved outside text paragraphs.
Where letters (such as V or L) are used to denote a shape rather than the letter, they have been transcribed as V or L for consistency with other, similarly used letters such as U.
Some minor obvious typographical errors have been corrected silently.
Page 108: "called Nobile’s pair" changed to "called Nobili’s pair".
Page 182: "shallacked" changed to "shellacked".
Page 184: "(A, B, and C) and A A, B B, and C C)" changed to "(A, B, and C and A A, B B, and C C)".
Dictionary: several entries have been moved to their proper alphabetical position.
Page 334: "modern applications of phenonema" changed to "applications of phenomena
Page 372: "Coil, Ruhmkoff" changed to "Coil, Ruhmkorff".
Page 382: "Daniells" changed to "Daniell".
Page 396: "graphite a native; form of carbon" changed to "graphite; a native form of carbon".
Page 401: "Ruhmkoff Coil. (See Coil, Ruhmkoff.)" changed to "Ruhmkorff Coil. (See Coil, Ruhmkorff.)"