STANDARD ELECTRICAL DICTIONARY.

A POPULAR DICTIONARY OF WORDS AND TERMS
USED IN THE PRACTICE OF ELECTRICAL ENGINEERING.


BY T. O'CONOR SLOANE, A.M., E.M., Ph.D.

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 assistance 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 space.

A word as to the use of the book and the system of its construction may
be given here. Each title or subject is defined once in the text. Where
a title is synonymous with one or more others the definition is only
given under one title, 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 title 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.

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 quantities it may be defined as referring to fixed units of quantity,
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 shellac, paraffin, sulphur
and resin, for instance, the absorption is very slight; with
gutta-percha, stearine, and glass, the absorption is relatively great.
The term is due to Faraday. Iceland spar seems almost or quite destitute
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."]


Accumulator.
(a) A term sometimes applied to the secondary or storage battery. (See
Battery, Secondary.)
(b) See Accumulator, Electrostatic
(c) See Accumulator, Water Dropping.
(d) See Wheel, Barlow's


Accumulator, Electrostatic.
Two conducting surfaces oppositely placed, and separated by a
dielectric and arranged for the opposite charging of the two surfaces,
constitute an accumulator, 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 ACCUMULATOR.


Accumulator, 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 illustration, 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.
This excitation causes the other stream of drops to work in the converse
way, raising the positive potential of F and C and A, thus causing the
left-hand drops to acquire a higher potential. This again raises the
potential of the right-hand drops, so that a constant accumulating
action is kept up. The outer coatings of the Leyden jars are connected
to earth to make it possible to raise the potential of their inner
coatings. In each case the drops are drawn by gravity into contact with
objects similarly excited in opposition to the electric repulsion. This
overcoming of the electric repulsion is the work done by gravity, and
which results in the development of electric energy.


10   STANDARD ELECTRICAL DICTIONARY.


Acidometer.
A hydrometer or areometer used to determine the specific gravity of
acid. They are employed in running storage batteries, to determine when
the charging is completed. (See Areometer.)


Aclinic Line.
A terrestrial element; the locus on the earth's surface of no
inclination of the magnetic needle; the magnetic equator. (See Magnetic
Elements.)


Acoustic Telegraphy.
The system of sound-reading in telegraphy, universally used in the Morse
system. The direct stroke of the armature of the electro-magnet and its
"back stroke" disclose to the ear the long and short strokes, dots and
lines, and long and short spaces as produced by the dispatcher of the
message. In the Morse system a special magnet and armature is used to
produce the sound called the "sounder;" in other systems, e. g.,
Steinheil's and Bright's apparatus, bells are used. (See Alphabets,
Telegraphic.)


Acoutemeter.
A Hughes audiometer or sonometer applied to determining the quality of a
person's hearing (See Hughes' Induction Balance,--Audiometer). The
central coil by means of a tuning fork and microphone with battery
receives a rapidly varying current tending to induce currents in the
other two coils. Telephones are put in circuit with the latter and pick
up sound from them. The telephones are applied to the ears of the person
whose hearing is to be tested. By sliding the outer coils back and forth
the intensity of induction and consequent loudness of the sounds in the
telephones is varied. The position when the sounds grow so faint as to
be no longer audible, gives the degree of delicacy of the person's
hearing. By using a single telephone the same apparatus affords a means
of testing the relative capacity of the right and left ears.


11  STANDARD ELECTRICAL DICTIONARY.


Actinic Rays.
The rays of light at the violet end of the spectrum; also the invisible
rays beyond such end, or the ether waves of short periods which most
strongly induce chemical change.


Actinism.
The power possessed by ether waves of inducing chemical change, either
of decomposition or of combination. The violet and ultra-violet end of
the spectrum of white light, generally speaking, represent the most
highly actinic rays.


Actinometer, Electric.
Properly an apparatus for measuring the intensity of light by its action
upon the resistance of selenium. A current produced by fixed
electro-motive force passing through the selenium affects a galvanometer
more or less according to the intensity of the light. It is more
properly an electric photometer. The term has also been applied to a
combination of a thermo-electric pile and galvanometer, the light
falling on the pile affecting the motions of the galvanometer.


Action, Local.
(a) The wasteful oxydation of the zinc in a galvanic battery due to
local impurities and variations in the composition of the zinc. These
act to constitute local galvanic couples which cause the zinc to
dissolve or oxydize, without any useful result. Amalgamation of the zinc
prevents local action. Chemically pure zinc is also exempt from local
action, and can be used in an acid battery without amalgamation. (See
Amalgamation.)

(b) The same term has been employed to indicate the eddy or foucault
currents in dynamo electric machines. (Sec Current, Foucault.)


Activity.
The rate of doing work; the work done per second by any expenditure of
energy. The activity of a horse-power is 550 foot lbs. per second, or
746 volt-coulombs per second. The practical electric unit is the
volt-ampere, often called the watt. (Sec Energy, Electric.)


Adapter.
A screw coupling to engage with a different sized screw on each end; one
of the uses is to connect incandescent lamps to gas-fixtures.


A. D. C.
Abbreviation for Anodic Duration Contraction, q. v.; a term in
electro-therapeutics.


Adherence, Electro-magnetic.
The adherence between surfaces of iron due to elcctro-magnetic
attraction. It has been applied to the driving-wheels of an engine and
rail, whose grip is increased by such action. In one method a deep
groove was cut around the wheel which was wound with a magnetizing coil.
Thus one rim becomes a north and the other a south pole, and the rail
completing the circuit acts as the armature. Such an arrangement
prevents a wheel from sliding. Electro-magnetic adherence has also been
employed to drive friction gear wheels. In one arrangement the two
wheels are surrounded by a magnetizing coil, under whose induction each
attracts the other, developing high adherence between their peripheries.


12  STANDARD ELECTRICAL DICTIONARY.



Fig. 3. ELECTRO-MAGNETIC CAR WHEEL.



Fig. 4. ELECTRO-MAGNETIC FRICTION GEAR.


Admiralty Rule of Heating.
The British Admiralty specifications for the permissible heating of
dynamos. It holds that at the end of a run of six hours no part of the
dynamo under trial shall show a rise of temperature greater than 11º C.
(20º F.) above the temperature of the air surrounding it. This is
thought to be a very stringent and unnecessarily high requirement.


Aerial Conductor.
An electric conductor carried from housetops, poles, or otherwise so as
to be suspended in the air, as distinguished from an underground or
submarine conductor.


Affinity.
The attraction of atoms and in some cases perhaps of molecules for each
other by the force of chemical attraction. When the affinity is allowed
to act or is carried out, a chemical change, as distinguished from a
physical or mechanical change, ensues. Thus if sulphur and iron are each
finely powdered and are mixed the change and mixture are mechanical. If
slightly heated the sulphur will melt, which is a physical change. If
heated to redness the iron will combine with the sulphur forming a new
substance, ferric sulphide, of new properties, and especially
characterized by unvarying and invariable ratios of sulphur to iron.
Such change is a chemical one, is due to chemical affinity, is due to a
combination of the atoms, and the product is a chemical compound.


13  STANDARD ELECTRICAL DICTIONARY.


Agir Motor.
The Anderson and Girdlestone motor. The term "agir" is made up from the
first portions of each name.


Agonic Line.
The locus of points on the earth's surface where the magnetic needle
points to the true north; an imaginary line determined by connecting
points on the earth's surface where the needle lies in the true
geographical meridian. Such a line at present, starting from the north
pole goes through the west of Hudson's Bay, leaves the east coast of
America near Philadelphia, passes along the eastern West Indies, cuts
off the eastern projection of Brazil and goes through the South Atlantic
to the south pole. Thence it passes through the west of Australia, the
Indian Ocean, Arabia, the Caspian sea, Russia and the White sea to the
North Pole. It crosses the equator at 70° W. and 55° E. approximately.
(See Magnetic Elements.)

Synonym--Agone.



[Transcriber's note: The file Earth_Declination_1590_1990.gif provided
by the U.S. Geological Survey (http://www.usgs.gov) is an animation of
the declination of the entire earth.]


Air.
Air is a dielectric whose specific inductive capacity at atmosphere
pressure is taken as 1. It is practically of exactly the same
composition in all places and hence can be taken as a standard. When dry
it has high resistance, between that of caoutchouc and dry paper.
Dampness increases its conductivity.

It is a mixture of oxygen and nitrogen, with a little carbonic acid gas
and other impurities. Its essential composition is:
Oxygen:     (by weight) 23.14     (by volume) 21   
Nitrogen:               76.86                 79

The specific inductive capacity varies for different pressures thus:
Approximate   (.001 mm., .0004 inch)   0.94 (Ayrton)  Vacuum                 ( 5 mm. , .2 inches )    0.9985 (Ayrton)
                                       0.99941 (Boltzman.)

The specific gravity of air under standard conditions 15.5° C (60° F.)
and 760 mm. barometric pressure (30 inches) is taken as unity as a
standard for gases.

[Transcriber's note: Argon accounts for 0.9340%. It was discovered in
1894, two years after this book.]


Air-Blast.
(a) In the Thomson-Houston dynamo an air-blast is used to blow away the
arc-producing spark liable to form between the brushes and commutator.
It is the invention of Prof. Elihu Thomson. The air is supplied by a
positive action rotary blower connected to the main shaft, and driven
thereby. The wearing of the commutator by destructive sparking is thus
prevented.

A drum H H is rotated, being mounted on the axis X of the dynamo. As it
rotates the three vanes are thrown out against the irregular shaped
periphery of the outer case T T. The arrow shows the direction of
rotation. The air is thus sent out by the apertures a a. O is the
oil-cup.

(b) The air-blast has also been used by Prof. Thomson in experiments
with high frequency currents of high potential. By directing a blast of
air against a spark discharge between ball terminals of an alternating
current, the nature of the current was changed and it became capable of
producing most extraordinary effects by induction.


14   STANDARD ELECTRICAL DICTIONARY.



Fig. 5. AIR BLOWER FOR THOMSON'S DYNAMO.


Air Condenser.
A static condenser whose dielectric is air. The capacity of an air
condenser in farads is equal to
  A / ( 4.452E12 * t )
in which A is the area of one sheet or sum of the areas of one set of
connected sheets in square inches and t is the thickness of the layer of
air separating them.

A convenient construction given by Ayrton consists in a pile of glass
plates P separated by little bits of glass F of known thickness, three
for each piece. Tin-foil T is pasted on both sides of each piece of
glass and the two coatings are connected. The tin-foil on each second
plate is smaller in area than that on the others. The plates are
connected in two sets, each set comprising every second plate. For A in
the formula the area of the set of smaller sheets of tin-foil is taken.
By this construction it will be seen that the glass does not act as the
dielectric, but only as a plane surface for attachment of the tin-foil.
Posts E E keep all in position. One set of sheets connects with the
binding post A, the other with B.

The capacity of any condenser with a dielectric of specific inductive
capacity i is given by the formula:
     ( i *A^1 ) / ( 4.452E12 * t1 )

The air condenser is used for determining the value of i for different
dielectrics.



Fig. 6. AIR CONDENSER.


15  STANDARD ELECTRICAL DICTIONARY.


Air Gaps.
In a dynamo or motor the space intervening between the poles of the
field magnet and the armature. They should be of as small thickness, and
of as extended area as possible. Their effect is to increase the
magnetic reluctance of the circuit, thereby exacting the expenditure of
more energy upon the field. They also, by crowding back the potential
difference of the two limbs, increase the leakage of lines of force from
limb to limb of the magnet.


Air Line Wire.
In telegraphy the portion of the line wire which is strung on poles and
carried through the air.


Air Pump, Heated.
It has been proposed to heat portions of a mercurial air pump to secure
more perfect vacua, or to hasten the action. Heating expands the air and
thus produces the above effects.


16   STANDARD ELECTRICAL DICTIONARY.

Air Pump, Mercurial.
An air pump operated by mercury. The mercury acts virtually as the
piston, and the actuating force is the weight of the column of mercury,
which must exceed thirty inches in height. There are many types.
Mercurial air pumps are largely used for exhausting incandescent lamp
chambers. (See Geissler Air Pump,--Sprengel Air Pump.)


Air Pumps, Short Fall.
A mercurial air pump in which the fall of mercury or the height of the
active column is comparatively small. It is effected by using several
columns, one acting after the other. A height of ten inches for each
column suffices in some forms. Enough columns must be used in succession
to make up an aggregate height exceeding 30 inches.



Fig. 7. BURGLAR ALARM SWITCH OR CIRCUIT BREAKER.



Fig. 8. BURGLAR ALARM SWITCH OR CIRCUIT BREAKER.


Alarm, Burglar.
A system of circuits with alarm bell extending over a house or
apartments designed to give notice of the opening of a window or door.
As adjuncts to the system the treads of the stairs are sometimes
arranged to ring the bell, by completing a circuit when trod on. Door
mats are also arranged to close circuits in like manner.


17  STANDARD ELECTRICAL DICTIONARY.


For doors and windows switches are provided which are open as long as
the door or window is closed, but which, on being released by opening
the door or windows, automatically close the circuit. The circuit
includes an alarm bell and battery, and the latter begins to ring and
continues until stopped, either by the closing of the door or by a
switch being turned. The connections are sometimes so contrived that the
reclosing of the door or window will not stop the bell from ringing.

The cuts show various switches for attachment to doors and windows. It
will be seen that they normally keep the circuit closed, and that it is
only open when pressure, as from a closed door, is brought upon them. In
the case of a door a usual place for them is upon the jamb on the hinge
side, where they are set into the wood, with the striking pin
projecting, so that as the door is closed the pin is pressed in, thus
breaking the circuit.

Sometimes the connections are arranged so as to switch on the electric
lights if the house is entered. Special annunciators showing where the
house has been entered are a part of the system. A clock which turns the
alarm on and off at predetermined hours is also sometimes used.

The circuits may be carried to a central station or police station. One
form of burglar alarm device is the Yale lock switch. This is a contact
attached to a Yale lock which will be closed if the wrong key is used,
completing a circuit and ringing a bell.



Fig. 9. BURGLAR ALARM SWITCH OR CIRCUIT BREAKER.


Alarm, Electric.
An appliance for calling attention, generally by
ringing a bell. It is used to notify of water-level in boilers or tanks,
of entrance of a house, or of other things as desired. It is evident
that any number of alarms could be contrived.


18   STANDARD ELECTRICAL DICTIONARY.


Alarm, Fire and Heat.
An alarm for giving notice of the existence of a conflagration. Such are
sometimes operated by a compound bar thermostat (see Thermostat), which
on a given elevation of temperature closes a circuit and rings an
electric bell. Sometimes the expansion of a column of mercury when
heated is used. This, by coming in contact with one or two platinum
points, completes a circuit, and rings the bell.

The identical apparatus may be used in living rooms, greenhouses.
factories and elsewhere, to give an alarm when the temperature rises or
falls beyond predetermined limits.


Alarm, Overflow.
An alarm to indicate an overflow of water has been suggested on the
lines of a contact completed by water, or of the elements of a battery
which would be made active by water. Thus two sheets of metal might be
separated by bibulous paper charged with salt. If these sheets were
terminals of a circuit including a bell and battery, when water reached
them the circuit would be closed and the bell would ring. It was also
proposed to use one copper and one zinc sheet so as to constitute a
battery in itself, to be thrown into action by moisture. These contacts
or inactive batteries could be distributed where water from an overflow
would be most likely to reach them.


Alarm, Water Level.
An alarm operated by a change of water level in a tank or boiler. By a
float a contact is made as it rises with the water. Another float may be
arranged to fall and close a contact as the level falls. The closing of
the contacts rings an electric bell to notify the attendant in charge.


Alcohol, Electrical Rectification of.
A current of electricity passed through impure alcohol between zinc
electrodes is found to improve its quality. This it does by decomposing
the water present. The nascent hydrogen combines with the aldehydes,
converting them into alcohols while the oxygen combines with the zinc
electrode.


Alignment.
The placing in or occupying of the same straight line. The bearings of a
shaft in dynamos, engines, and other machinery have to be in accurate
alignment.


Allotropy.
The power of existing in several modifications possessed by some
substances, notably by chemical elements. Instances of the allotropic
state are found in carbon which exists as charcoal, as graphite
(plumbago or black lead), and as the diamond. All three are the same
elemental substance, although differing in every physical and electrical
property.


19   STANDARD ELECTRICAL DICTIONARY.


Alloy.
A mixture, produced almost universally by fusion, of two or more metals.
Sometimes alloys seem to be chemical compounds, as shown by their having
generally a melting point lower than the average of those of their
constituents. An alloy of a metal with mercury is termed an amalgam. An
important application in electricity is the use of fusible alloys for
fire alarms or for safety fuses. German silver is also of importance for
resistance coils, and palladium alloys are used for unmagnetizable
watches. An alloy of wrought iron with manganese is almost
unmagnetizable, and has been proposed for use in ship building to avoid
errors of the compass.

Alloys or what are practically such can be deposited by electrolysis in
the electro- plater's bath. We give the composition of some alloys
interesting to the electrician.

  Solder:   Lead   1 part   Tin   2 parts
             "      "       "    1  "
             "      "       "    2  "

German Silver: Copper, 2 parts; Nickel, 1 part;
               Zinc, 1 part (used for resistances).

Platinum, Silver Alloys: Platinum, 1 part;
                         silver, 2 parts (used for resistances.)

Palladium alloys for watch springs. (See Palladium.)


Alphabet, Telegraphic.
The combinations of sounds, of dots and dashes marked on paper, of
right-hand and left-hand deflections of a needle, of bells of different
notes, or of other symbols by which a fixed combination is expressed for
each character of the alphabet, for numerals, and for punctuation. While
the code is designed for telegraphic uses it can be used not only for
the conveyance of signals and messages by the electrical telegraphs, but
also by any semaphoric or visual system, as by flashes of light,
movements of a flag or even of the arms of the person signalling.

In the English and continental needle telegraphy in which the message is
transmitted by the movements of an index normally vertical, but
oscillating to one side or the other under the influence of the current,
the latter being controlled by the transmitter of the message, the left
hand swings of the needle are interpreted as dots, the right hand as
dashes.

This system enables one alphabet to be translated into the other, or
virtually one alphabet answers for both Morse and needle transmitters.

There are two principal telegraphic alphabets, the American Morse and
the International codes. They are very similar, their essential
distinction being that spaces are used in the American code, while they
are excluded from the International code.

In the American Morse system the message is now universally received by
sound. (See Sounder--Sound Reading.)


20   STANDARD ELECTRICAL DICTIONARY.


The two codes or telegraphic alphabets are given here.

THE INTERNATIONAL ALPHABET.
     Parenthesis,             - . - - . -
  Understand,              ... - .
  I don't understand,      ..-- ....--..
  Wait,                    .-. . .
  Erase,                   ...   ...   ...
  Call signal,             -.-.-.-
  End of message,          .-.-.-.
  Cleared out all right,   .-..-..-.
  A  .-    L  .-..  W  .--
  B  -...  M  --    X  -..-
  C  -.-.  N  -.    Y  -.--
  D  -..   O  ---   Z  --..
  E  .     P  .--.
  F  ..-.  Q  --.-  Ch ----
  G  --.   R  .-.   Ä  .-.-
  H  ....  S  ...   Ö  ---.
  I  ..    T  -     Ü  ..--
  J  .---  U  ..-   É  ..-..
  K  -.-   V  ...-  Ñ  --.--

NUMERALS
  1  .----  4  ....-  8  ---..
  2  ..---  5  .....  9  ----.
  3  ...--  6  -....  0  -----
            7  --...


[Transcriber's note: The original image of the dot/dash pattern is somewhat
ambiguous. Since there may be differences from contemporary specifications,
the original image is included.]


[Image of page 20: THE INTERNATIONAL ALPHABET.]


21  STANDARD ELECTRICAL DICTIONARY.


PUNCTUATION, ETC.,

  Period (.)         ...   ...
  Comma (,)          .-.-.-
  Query(?)           ..--..
  Exclamation (!)    --..--
  Apostrophe (')     .----.
  Hyphen (-)         -....-
  Fresh paragraph,   .-.-..
  Inverted commas,   -..-.

THE AMERICAN ALPHABET.
  A  .-       L  ----(Continuous)  W  .--
  B  -...     M  --                X  .-..
  C  ..s.     N  -.                Y  ..s..
  D  -..      O  .s.               Z  ….
  E  .        P  .....
  F  .-.      Q  ..-.              Ch ----
  G  --.      R  .s..              Ä  .-.-
  H  ....     S  ...               Ö  ---.
  I  ..       T  -                 Ü  ..--
  J  - . - .  U  ..-               É  ..-..
  K  -.-      V  ...-              Ñ  --.--

NUMERALS
  1  .--.    4  ....-     8  -....
  2  ..-..   5  ---       9  -..-
  3  ...-.   6  ... ...   0  -----(Continuous)
             7  --..

[Transcriber's Note: The "s" in the American Code indicates a "space". I
leave the following to the reader's imagination. See the original
image.]

Comma (,)
Semicolon (;)
Colon (:)
Colon Dash (:~)
Period (.)
Interrogation (?)
Exclamation (!)
Dash (-)
Hyphen (-)
Pound Sterling (£)
Shilling Mark ( )



[Image of page 21: THE AMERICAN ALPHABET.]


22   STANDARD ELECTRICAL DICTIONARY.


[Transcriber's Note: I leave these to the reader's imagination. See the
following original image.]

Dollars ($)
Decimal Point (.)
Cents (c)
Paragraph ()
Pence (d.)
Fractional Mark (--)
Capitalized Letter
Italics or Underline
Colon followed by Quotation :"
Parenthesis (   )
Brackets [   ]
Quotation Marks " "
Quotation within a Quotation " ' ' "



[Image of page 22: THE AMERICAN ALPHABET.]


The principal differences in the two codes are the use of spaces in the
American code, such being excluded from the International code. This
affects the letters C, R, Y, & Z.

The following diagram, due to Commandant Perian, enables the letter
corresponding to an International code sign to be rapidly found with the
exception of R.

             <- dot       start         dash   ->
               /                           \
              E                             T
         /          \                /             \
       I              A             N                M
    /    \          /    \        /    \         /      \
   S      U        R      W       D      K       G       O
 /  \    / \     / \    /  \    /  \     /  \    /  \    /  \
H   V   F   U   L   A   P   J   B   X   C   Y   Z    Q  Ô   CH
Fig. 10. Diagram for translating the Morse Alphabet.

In order to find what letter corresponds to a given sign, starting from
the top of the diagram, each line is traced down to a bifurcation,
taking the right hand line of each bifurcation for a dash, and the left
hand line for a dot, and stopping when the dots and dashes are used up.
Thus, for example,

the signal -.- -   leads us to the letter d,

the signal - - - - to the letter j and so on.


23  STANDARD ELECTRICAL DICTIONARY.


Alternating. adj.
Term descriptive of a current changing periodically in
direction. (See Current, Alternating.)

Synonyms--Oscillatory--periodic--undulatory--harmonic.

Alternating Current Arc.
The arc produced by the alternating current. It presents several
peculiarities. With an insufficient number of alternations per second it
goes out. As the carbons wear away equally it is adopted for such lamps
as the Jablochkoff candle, (see Candle, Jablochkoff). As no crater is
formed the light is disseminated equally both up and down. For this
reason to get full downward illumination a reflector is recommended.


Alternating Current System.
A system of electric distribution employing the alternating current. For
transmission in the open air or in conduits a high potential circuit is
used, from 1,000 to 10,000 volts being maintained at the central
station. Two leads unconnected at the end lead from the station. Where
current is desired a converter or transformer (see Converter) is placed,
whose primary is connected to the two leads bridging the interval
between them. From the secondary the house leads are taken with an
initial potential in some cases of 50 volts. The converters are thus all
placed in parallel. By law or insurance rules the converters are
generally kept outside of buildings. Where no secondary current is taken
from the converters very little primary current passes them on account
of their counter-electromotive force. As more secondary current is taken
the primary increases and this accommodation of one to the other is one
of the interesting and valuable features. Street lamps are sometimes
connected in series. Each lamp in such case is in parallel with a small
coil with iron core. While the lamp is intact little current passes
through the coil. If the lamp is broken, then the converter impedes the
current by its spurious resistance, q. v., just enough to represent and
replace the resistance of the extinguished and broken lamp filament.
(See Meter, Alternating Current; Motor, Alternating Current.)


Alternation.
The change in direction of a current. The number of such changes is
expressed as number of alternations; thus a current may have a frequency
of 500 or 20,000 alternations per second.

[Transcriber's note: One alternation per second is now called one hertz.]


Alternation, Complete.
A double alternation; a change from one direction
to the other and back again to the original phase. A symbol derived from
its graphic representation by a sine curve is used to indicate it. The
symbol is  ~


24   STANDARD ELECTRICAL DICTIONARY.


Alternative Path.
A second path for a current appearing as a disruptive
discharge. Where two paths are offered the discharge, as it is of
alternating or oscillatory type, selects the path of least
self-induction. Thus a thick bar of copper, with no air gap, may be
abandoned by the current in favor of a small iron wire with an air gap,
but which has less self-induction.

The lightning arresters, q. v., for the protection of telegraph offices
are sometimes based on these principles. A path of very high resistance
but of small self-induction is offered between the line and the earth.
This the lightning discharge selects in preference to the instruments
with their iron cores, as the latter are of very high self-induction.


Alternator.
A dynamo electric generator supplying an alternating current. (See
Dynamo, Alternating Current.)

Synonym--Alternating current generator or dynamo.


Alternator, Constant Current.
An alternating current dynamo supplying a current of unvarying virtual
amperage. Alternators of this type are constructed with an armature of