Synonym--AEolotropic.

Annealing, Electric.

Annealing by the heat produced by the pa.s.sage of the electric current through the body to be annealed. The object is clamped or otherwise brought into a circuit, and a current strong enough to heat it to redness, or to the desired temperature is pa.s.sed through it.

Annunciator.

An apparatus for announcing a call from any place to another, as from a living-room to an office in a hotel, or for announcing the entering of any given room or window in a building protected by a burglar alarm.

A usual system comprises for each annunciator an electro-magnet. Its armature is normally held away from its poles by a spring, and when in that position a latch connected to the armature holds a little shutter.

When by a push-b.u.t.ton or other device a current is sent through a circuit which includes the electro-magnet the armature is attracted, this releases the latch and the shutter drops. In dropping it displays a number, letter or inscription which indicates the locality of the push-b.u.t.ton or other circuit-closing device. Often annunciators are connected in circuit with a bell.

Fig. 14. ANNUNCIATOR.

35 STANDARD ELECTRICAL DICTIONARY.

Annunciator Clock.

A clock operating an annunciator by making contact at determined times.

Annunciator Drop.

The little shutter which is dropped by some forms of annunciators, and whose fall discloses a number, character or inscription, indicating whence the call was sent.

Fig. 15. DROP ANNUNCIATOR.

Fig. 16. ANNUNCIATOR DETACHING MECHANISM.

Annunciator, Gravity Drop.

An annunciator whose operations release shutters which fall by gravity.

Annunciator, Needle.

A needle annunciator is one whose indications are given by the movements of needles, of which there is usually a separate one for each place of calling.

Annunciator, Swinging or Pendulum.

An annunciator which gives its indications by displacing from its vertical position a pendulum or vertically suspended arm.

36 STANDARD ELECTRICAL DICTIONARY.

Anodal Diffusion.

A term in electro-therapeutics; the introduction of a medicine into the animal system by using a sponge-anode saturated with the solution of the drug in question. On pa.s.sing a current the desired result is secured by cataph.o.r.esis, q. v.

Anode.

The positive terminal in a broken metallic or true conducting circuit; the terminal connected to the carbon plate of a galvanic battery or to its equivalent in case of any other generator. In general practice it is restricted to the positive terminal in a decomposition or electrolytic cell, such as the nickel anode in a nickel-plating bath or the anode of platinum in a gas voltameter. It is the terminal out of or from which the current is supposed to flow through the decomposition cell. In electro-therapeutics the term is used simply to indicate the positive terminal. In an electrolytic cell the electro-negative substance or anion goes to the anode. Hence, it is the one dissolved, if either are attacked. The nickel, copper or silver anodes of the electroplater dissolve in use and keep up the strength of the bath. The platinum anode in a gas voltameter is unattacked because the anion cannot act upon it chemically.

Anodic Closure Contraction.

A physiological change in a living subject produced by the closing of the electric current; the muscular contraction which takes place beneath the anode applied to the surface of the body when the circuit is closed, the kathode being applied elsewhere; it is due, presumably, to direct action on the motor nerve. It is a term in electro-therapeutics. It is the converse of anodic opening contraction, q. v. An abbreviation A. C.

C. is often used to designate it.

Anodic Duration Contraction.

A term in electro-therapeutics. On the opening or closing of an electric circuit, the anode of which is placed over a muscle, a contraction is observed (see Anodic Closure Contraction--Anodic Opening Contraction).

The above term is used to designate the duration of such contraction. An abbreviation A. D. C. is often used to designate it.

Anodic Opening Contraction.

The converse of Anodic Closure Contraction, q. v.; it is the contraction of living muscle beneath or near the anode where the circuit, including such anode and the body in its course, is closed; a physiological phenomenon observed in electro-therapeutics to which branch of science the term belongs. An abbreviation A. O. C. is often used to designate it.

Anodic Reactions.

A term in electro-therapeutics; the diagnosis of disease by the actions of the tissue near the anode of a circuit.

Anti-Induction Conductor.

A conductor constructed to avoid induction effects in the conducting element. Many kinds have been made. A tubular metal shield or envelope which may be grounded will protect an enclosed conductor to some extent.

Or the conductor may be a double wire twisted around itself, one branch being used for the regular and the other for the return circuit, thus const.i.tuting a closed metallic circuit. The inductive effects are due to interrupted or varying currents in neighboring wires and circuits. Many anti-induction conductors have been invented and patented.

37 STANDARD ELECTRICAL DICTIONARY.

Anti-magnetic Shield.

In general terms a hollow screen of soft iron designed to protect any ma.s.s of steel behind or enclosed by it from magnetization by any magnet near it, such as a dynamo field magnet. This it does by concentrating the lines of force within its own ma.s.s, so that the s.p.a.ce within it or enclosed by it is comparatively free from lines of force. It is often applied to watches, and is virtually an iron case in which they are enclosed.

Antimony.

A metal, one of the elements, atomic weight, 122: equivalent, 40.6 and 24.4; valency, 3 and 5; specific gravity, 6.8.

It is a conductor of electricity.

Relative resistance, compressed (silver = 1), 23.60 Specific resistance, 35.50 microhms.

Resistance of a wire, (a) 1 foot long, weighing 1 grain, 3.418 ohms.

(b) 1 foot long, 1/1000 inch thick, 213.6 "

(c) 1 meter long, weighing 1 gram, 2.384 "

(d) 1 meter long. 1 millimeter thick, 0.4521 "

Resistance of a 1-inch cube, 13.98 microhms.

Approximate percentage resistance per degree C.

(1.8? F. at 20? C. 88? F.) 0.389 per cent.

Elcctro-chemical equivalent (hydrogen = .0105) .2560 (See Thermo-Electric Series.)