Fune 25, 1885] 
viations throughout, except in such cases as that of quoting 
direct from some other author. 
It will be observed in this list that in most cases the first 
English or Greek letter of the word has been used. Those 
relating to the metric system have been copied from the French 
edition of Hospitalier’s ‘‘ Electrician’s Pocket-book,” which are 
no doubt copied from the list decided upon by the International 
Commission on the Metre, with a few omissions and additions 
by the author. 
The Greek letters 7, «, € are universally adopted—m for 
the ratio of the circumference of a circle to its diameter, m for 
the coefficient of friction, and « for the base of Napierian 
logarithms. 
Metric Abbreviations 
m. for metre. 
cm. 3, centimetre. 
mn. ,, millimetre. 
m? 5, Metre-square, 
m3 >»  metre-cube. 
en » centimetre-square. 
3 », centimetre-cube. 
gm. ,, gramme. 
mg. ,,  milligramme. 
kg. >, kilogramme. 
kgm. ,, kilogrammetre. 
&e, &e. 
temp. ,, temperature. 
res. s, resistance. 
gd. ,, gramme-degré. 
kg.d. ,, kilogramme-degre. 
Lkictrical Abbreviations, Notation, and Symbols 
When a capital letter is used for the symbol, then small 
capitals or italics with suffixes, 1, 2, 3, &c., may be used for 
parts making up a whole. For example—L for length, 14, Ly, L3, 
&c., or /,, 4, 23, for different lengths, or parts of L. 
Fundamental and Derived Mechanical Units 
iy for Length. 
M 3> Mass. 
a IG », Time. 
Vorzv », Velocity. 
A ora », Acceleration. 
F »» Force. 
5 », dyne ; ¢.g. 106 = 10 dynes. 
Ww 3, Work. 
w 3, Weight. 
ft.Ib. », foot pound. 
H.P. or } ,, Horse-power. 
LHP. ;, Indicated horse-power. 
B.H.P. », Brake horse-power. 
Other Common Synibols allied to Mechanical Work 
SS) for Speed or Stress. 
Dord 3, Diameter. 
r y) radius. 
® 5, angular velocity = 2m in radians per 
second, 
», acceleration due to gravity. 
N or 7, 7, &c. ,, number of revolutions. 
-s », second; e.g. 3h 5™ ros = 3 hours 5 
minutes 10 seconds. 
7, T) 73, &c. ,, temperatures, absolute. 
Ort fy tg, &C. 4, as common, 
Practical Electric Units 
The astronomical method of putting the small letters above 
the line of the figures, as in the case of the example 32" 5™ 105 
(3 hours 5 minutes Ito seconds), has not been followed in the 
following examples, as mathematicians object to the system, the 
letters appearing as if they were powers. Neither will they 
readily agree to suffixes, as suffixes have been already adopted 
by them to distinguish between things of the same kind. The 
author has therefore written the distinguishing letters on a level 
with the figures: for example, 10, stands for 10 ohms (the 
methods ro* and Io, being both objectionable). 
C.G.S. for centimetre, gramme, second. 
R 5, Resistance. 
p y; Specific resistance. 
NABORE 
187 
w for ohm ; ¢.g. 10,, = 10 ohms. 
ke) », megohm ; ¢.g. 10.9 = 10 megohms. 
Cc s, Current. 
Important Electrical Definitions 
A >, Amperes ; e.g, loA = 10 amperes. 
a », milliamperes ; ¢.g. 10a = 10 milliamperes. 
E ;, Electro-motive force, or E.M.F. 
Vv », volts; @¢. Lov = Io volts. 
Kk », Capacity. 
o »» Specific inductive capacity. 
® », farads ; e.g. 106 = 10 farads. 
» »» microfarads ; e.g. 10m = 10 microfarads, 
Q >» Quantity (coulombs). 
1p 3, Power. 
W », Watts, or Watt power.? 
W », Work in Joules. 
H 7 eLeat ine ses. 
IJ ,, Joule’s equivalent = 42 x 10° ergs, or work 
spent on ‘2405 gm. of H,O raised by 1° cent. 
E ; 
Cc R (Ohm’s law). 
Ex C=¢ R= = = W (Watt powers). 
2 1S hay Be 
ID (Gah = (CAIK WE = = = EQ = W (Joules). 
ICON GIN we _ BO _ Ww 
J J JR i 
= W x ‘2405 = g.d. or gramme degrees. 
= Electro-chemical equivalent. 
Magnetism 
N for North pole of a magnet, painted red. 
Si); south 5D A 55 blue. 
m ,, magnet strength (of pole) or quantity of mag- 
netism. 
Z », distance between the poles of a magnet. 
M or mZ ,, moment of a magnet. 
Jorl ,, Intensity of magnetisation. 
Ss 5, cross section of a magnet. 
mp ,, magnetic potential. 
& 4, magnetic permeability. 
K », magnetic susceptibility. a, 
H__,, Horizontal intensity of terrestrial magnetism. 
», angle of deflection. 
divisions deflection, as in mirror galvanometer. 
», radius (mean) of a coil or solenoid. : 
», number of anything ; e.g. turns of wire in a 
coil or galvanometer. 
Take Tangent Galvanometer Formule, as an example to illus- 
trate the above :— 
G 
s 
Fs 
aL 
B 
Gurrent) Ce. EL ”~.tan 6 
27TH 
G for Galvanometer or galv. res. : 
s  ,, shunt res. for galyanometer oRU=rB Ee if Sy ight 
ry ,, resistance coils Gaas 
B_ ,, Battery or battery res. 
I By adopting the term ‘‘ Watt power,” there can be no doubt what a 
Watt means. , i 
2 See Munro and Jamieson’s “‘ Electrical Pocket-book,” p. 65. 
