Quantity.
Electro-magnetic. Quantity is determined electro-magnetically by the
measurement of current intensity for a second of time: its dimensions
are therefore given by multiplying intensity or current strength by
time. The dimensions of intensity are
( (M^.5) * (L^.5) ) / T
therefore the dimensions of electro-magnetic quantity are
( ( (M^.5) * (L^.5) ) / T ) * T = ( (M^.5) * (L^.5) )
Quantity, Electro-magnetic, Practical Unit of.
The quantity of electricity passed by a unit current in unit time; the
quantity passed by one ampere in one second; the coulomb.
It is equal to 3E9 electrostatic absolute units of quantity and to 0.1
of the electro- magnetic absolute unit of quantity.
One coulomb is represented by the deposit of
.00111815 gram, or .017253 grain of silver,
.00032959 gram, or .005804 grain of copper,
.0003392 gram, or .005232 grain of zinc.
If water is decomposed by a current each coulomb is represented by the
cubic centimeters of the mixed gases (hydrogen and oxygen) given by the
following formula.
( 0.1738 * 76 * (273 + Cº ) ) / ( h * 273 )
in which Cº is the temperature of the mixed gases in degree centigrade
and h is the
pressure in centimeters of mercury column; or by
( 0.01058 * 30 (491 + Fº - 32) ) / (h * 491 )
for degrees Fahrenheit and inches of barometer.
[Transcriber's note: 6.24150962915265E18 electrons is one coulomb.]
Quantity, Electrostatic.
Quantity is determined electro-statically by the repulsion a charge of
given quantity exercises upon an identical charge at a known distance.
The force evidently varies with the product of the two quantities, and
by the law of radiant forces also inversely with the square of the
distance. The dimensions given by these considerations is Q * Q/(L*L).
This is the force of repulsion. The dimensions of a force are
(M * L) /(T^2). Equating these two expressions we have:
(Q^2)/(L^2) = (M*L)/(T^2)
or
Q = ((M^.5)*(L^1.5)) / T
which are the dimensions of electrostatic quantity.
Quantity, Meter.
An electric meter for determining the quantity of electricity which
passes through it, expressible in coulombs or ampere hours. All
commercial meters are quantity meters.