The Standard Electrical Dictionary.
by T. O"Conor Slone.
PREFACE
The purpose of this work is to present the public with a concise and practical book of reference, which it is believed will be appreciated in this age of electricity. The science has expanded so much that the limits of what may be termed strictly a dictionary of the present day would a few years ago have sufficed for an encyclopedia. It follows that an encyclopedia of electricity would be a work of great size. Yet a dictionary with adequate definitions, and kept within the closest limits by the statement of synonyms, and by the consigning of all the innumerable cross-references to a concise index will be far more than a mere dictionary in the ordinary sense of the term.
Duplication of matter is to be avoided. This makes many definitions appear short. Yet, by the a.s.sistance of the reader"s own general knowledge, and by referring to the very complete index, almost any subject can be found treated in all its aspects. There are exceptions to this statement. So much has been done in the way of mechanical detail, so many inventions in telegraphy and other branches have sprung into prominence only to disappear again, or to be modified out of recognition, that to embody descriptions of many ingenious and complicated apparatus has been absolutely impossible for want of s.p.a.ce.
A word as to the use of the book and the system of its construction may be given here. Each t.i.tle or subject is defined once in the text. Where a t.i.tle is synonymous with one or more others the definition is only given under one t.i.tle, and the others appear at the foot of the article as synonyms. It may be that the reader is seeking the definition of one of these synonyms. If so a reference to the index shows him at once what page contains the information sought for. The use of an index in a work, necessarily of an encyclopedic form, will be appreciated by all users of this book.
vi PREFACE.
Where a t.i.tle embraces several words, all orders of the words will be cited in the index. To make the operation of finding references easy this rule has been carried out very fully.
It is customary to regard electricity as a growing science. It is unquestionably such, but the multiplication of terms and words is now not nearly so rapid as it has been, and the time for the compiling of a work of this character seems most propitious. It is hoped that the public will indulgently appreciate the labor it has entailed on all concerned in its production.
SYMBOLS AND ABBREVIATIONS.
adj. Adjective.
v. Verb.
q.v. "Which see."
/ A mark of division, as A/B, meaning "A divided by B."
./. The same as above.
[Transcriber"s note: / will be subst.i.tuted for this divide symbol.]
= A mark of equality, meaning "is equal to."
X A mark of multiplication, meaning "multiplied by."
[Transcriber"s note: * will be subst.i.tuted for this divide symbol.]
Fractional exponents indicate the roots expressed by their denominators and the powers expressed by their numerators. Thus, A^1/2 means the "square root of A;" A^1/3 means the "cube root of A;" B^3/2 means the "square root of the cube or third power of B."
The use of powers of ten, as 10^10, 10^11, as multipliers, will be found explained at length in the definition "Ten, Powers of."
vii STANDARD ELECTRICAL DICTIONARY
A.
Abbreviation for anode, employed in text relating to electro-therapeutics. It is sometimes written An.
Abscissa.
In a system of plane co-ordinates (see Co-ordinates) the distance of any point from the axis of ordinates measured parallel to the axis of abscissas.
In the cut the abscissa of the point a is the line or distance a c.
Fig. 1. AXES OF CO-ORDINATES.
Absolute. adj.
In quant.i.ties it may be defined as referring to fixed units of quant.i.ty, and it is opposed to "relative," which merely refers to the relation of several things to each other. Thus the relative resistance of one wire may be n times that of another; its absolute resistance might be 5 ohms, when the absolute resistance of the second wire would be 5/n ohms. A galvanometer gives absolute readings if it is graduated to read directly amperes or volts; if not so graduated, it may by "calibration" q. v. be made to do practically the same thing.
8 STANDARD ELECTRICAL DICTIONARY.
Absolute Measurement.
Measurement based upon the centimeter, gram, and second. (See Centimeter-Gram-Second System.)
Absolute Temperature.
Temperature reckoned from absolute zero (see "Zero, Absolute"). It is obtained by adding for the centigrade scale 273, and for the Fahrenheit scale 459, to the degree readings of the regular scale.
Absorption, Electric.
A property of the static charge. When a Leyden jar is being charged it dilates a little and the capacity increases, so that it can take a little more charge for a given potential difference existing between its two coatings. This phenomenon occurs with other static condensers, varying in degree with the dielectric. With sh.e.l.lac, paraffin, sulphur and resin, for instance, the absorption is very slight; with gutta-percha, stearine, and gla.s.s, the absorption is relatively great.
The term is due to Faraday. Iceland spar seems almost or quite dest.i.tute of electric absorption.
A. C. C.
Symbol of or abbreviation for "anodic closure contraction" q. v.
Acceleration.
The rate of change of velocity. If of increase of velocity it is positive; if of decrease, it is negative. It can only be brought about by the exercise of force and is used as the measure of or as determining the unit of force. It is equal to velocity (L/T) imparted, divided by time (T); its dimensions therefore are L/(T^2). The c. g. s. unit of acceleration is one centimeter in one second.
[Transcriber"s note: The unit of acceleration is "centimeters per second per second."]
Acc.u.mulator.
(a) A term sometimes applied to the secondary or storage battery. (See Battery, Secondary.) (b) See Acc.u.mulator, Electrostatic (c) See Acc.u.mulator, Water Dropping.
(d) See Wheel, Barlow"s
Acc.u.mulator, Electrostatic.
Two conducting surfaces oppositely placed, and separated by a dielectric and arranged for the opposite charging of the two surfaces, const.i.tute an acc.u.mulator, sometimes termed a condenser. As this arrangement introduces the element of a bound and of a binding charge, the electrostatic capacity of such is greater than that of either or of both of its component surfaces. The thinner the dielectric which separates the conducting surfaces, and the larger the surfaces the greater is the capacity; or the less will be the potential difference which a given charge will establish between its two coatings. The nature of the dielectric also determines its capacity. (See Capacity, Specific Inductive.)
9 STANDARD ELECTRICAL DICTIONARY.
Fig. 2. SIR WILLIAM THOMSON"S WATER-DROPPING ACc.u.mULATOR.
Acc.u.mulator, Water Dropping.
This is also known as Sir William Thomson"s Water-Gravity Electric Machine. It is an apparatus for converting the potential energy of falling water drops, due to gravity, into electric energy. Referring to the ill.u.s.tration, G represents a bifurcated water pipe whose two faucets are adjusted to permit a series of drops to fall from each. C and F are two metallic tubes connected by a conductor; E and D are the same. Two Leyden jars, A and B, have their inner coatings represented by strong sulphuric acid, connected each to its own pair of cylinders, B to D and E, and A to F and C. The outer coatings are connected to earth, as is also the water supply. One of the jars, say A, is charged interiorily with positive electricity. This charge, C and F, share with it, being in electric contact therewith. Just before the drops break off from the jet leading into C, they are inductively charged with negative electricity, the positive going to earth. Thus a series of negatively excited drops fall into the metal tube D, with its interior funnel or drop arrester, charging it, the Leyden jar B, and the tube E with negative electricity.