Compa.s.s, Spirit.

A form of mariner's compa.s.s. The bowl or case is hermetically sealed and filled with alcohol or other nonfreezing liquid. The compa.s.s card is made with hollow compartments so as nearly to float. In this way the friction of the pivot or point of support is greatly diminished, and the compa.s.s is far more sensitive.

Compa.s.s, Surveyor's.

A species of theodolite; a telescope with collimation lines, mounted above a compa.s.s, so as to be applicable for magnetic surveys. Its use is to be discouraged on account of the inaccuracy and changes in declination of the magnetic needle.

144 STANDARD ELECTRICAL DICTIONARY.

Compensating Resistances.

In using a galvanometer shunt the total resistance of the circuit is diminished so that in some cases too much current flows through it; in such case additional resistance, termed as above, is sometimes introduced in series. The shunt in parallel with the galvanometer is thus compensated for, and the experimental or trial circuit does not take too much current.

Complementary Distribution.

Every distribution of electricity has somewhere a corresponding distribution, exactly equal to it of opposite electricity; the latter is the complimentary distribution to the first, and the first distribution is also complimentary to it.

Component.

A force may always be represented diagrammatically by a straight line, terminating in an arrow-head to indicate the direction, and of length to represent the intensity of the force. The line may always be a.s.sumed to represent the diagonal of a parallelogram, two of whose sides are represented by lines starting from the base of the arrow, and of length fixed by the condition that the original force shall be the diagonal of the parallelogram of which they are two contiguous sides; such lines are called components, and actually represent forces into which the original force may always be resolved. The components can have any direction.

Thus the vertical component of a horizontal force is zero; its horizontal component is equal to itself. Its 450 component is equal to the square root of one-half of its square.

Condenser.

An appliance for storing up electrostatic charges: it is also called a static acc.u.mulator. The telegraphic condenser consists of a box packed full of sheets of tinfoil. Between every two sheets is a sheet of paraffined paper, or of mica. The alternate sheets of tinfoil are connected together, and each set has its own binding post. (See Acc.u.mulator, Electrostatic.)

Condenser, Sliding.

An apparatus representing a Leyden jar whose coatings can be slid past each other. This diminishes or increases the facing area, and consequently in almost exactly similar ratio diminishes or increases the capacity of the condenser.

Conductance.

The conducting power of a given ma.s.s of specified material of specified shape and connections. Conductance varies in cylindrical or prismatic conductors, inversely as the length, directly as the cross-section, and with the conductivity of the material. Conductance is an attribute of any specified conductor, and refers to its shape, length and other factors. Conductivity is an attribute of any specified material without direct reference to its shape, or other factors.

Conduction.

The process or act of conducting a current.

145 STANDARD ELECTRICAL DICTIONARY.

Conductivity.

The relative power of conducting the electric current possessed by different substances. A path for the current through the ether is opened by the presence of a body of proper quality, and this quality, probably correlated to opacity, is termed conductivity. There is no perfect conductor, all offer some resistance, q. v., and there is hardly any perfect non-conductor. It is the reverse and reciprocal of resistance.

Conductivity, Specific.

The reciprocal of specific resistance. (See Resistance--Specific.)

Conductivity, Unit of.

The reciprocal of the ohm; it is a more logical unit, but has never been generally adopted; as a name the t.i.tle mho (or ohm written backwards) has been suggested by Sir William Thomson, and provisionally adopted.

Conductivity, Variable.

The conductivity for electric currents of conductors varies with their temperature, with varying magnetization, tension, torsion and compression.

Conductor.

In electricity, anything that permits the pa.s.sage of an electric current. Any disturbance in the ether takes the form of waves because the ether has rest.i.tutive force or elasticity. In a conductor, on the other hand, this force is wanting; it opens a path through the ether and a disturbance advances through it from end to end with a wave front, but with no succession of waves. This advance is the beginning of what is termed a current. It is, by some theorists, attributed to impulses given at all points along the conductor through the surrounding ether, so that a current is not merely due to an end thrust. If ether waves preclude a current on account of their rest.i.tutive force, ether waves cannot be maintained in a conductor, hence conductors should be opaque to light, for the latter is due to ether waves. This is one of the more practical every day facts brought out in Clerk Maxwell's electromagnetic theory of light. The term conductor is a relative one, as except a vacuum there is probably no substance that has not some conducting power. For relative conducting power, tables of conductivity, q. v., should be consulted.

The metals beginning with silver are the best conductors, gla.s.s is one of the worst.

[Transcriber's note: See "ether" for contemporary comments on this now discarded concept.]

Conductor, Anti-Induction.

A current conductor arranged to avoid induction from other lines. Many kinds have been invented and made the subject of patents. A fair approximation may be attained by using a through metallic circuit and twisting the wires composing it around each other. Sometimes concentric conductors, one a wire and the other a tube, are used, insulated, one acting as return circuit for the other.

Conductor, Conical.

A prime conductor of approximately conical shape, but rounded on all points and angles. Its potential is highest at the point.

146 STANDARD ELECTRICAL DICTIONARY.

Conductor, Imbricated.

A conductor used in dynamo armatures for avoiding eddy currents, made by twisting together two or more strips of copper.

Conductor, Prime.

A body often cylindrical or spherical in shape, in any case with no points or angles, but rounded everywhere, whose surface, if the conductor itself is not metallic, is made conducting by tinfoil or gold leaf pasted over it. It is supported on an insulating stand and is used to collect or receive and retain static charges of electricity.

Conductors, Equivalent.

Conductors of identical resistance. The quotient of the length divided by the product of the conductivity and cross-section must be the same in each, if each is of uniform diameter.

Conjugate. adj.

Conjugate coils or conductors are coils placed in such relation that the lines of force established by one do not pa.s.s through the coils of the other. Hence variations of current in one produce no induced currents in the other.

Connect. v.

To bring two ends of a conductor together, or to bring one end of a conductor in connection with another, or in any way to bring about an electrical connection.

Connector.