The gradual increase or creeping up of magnetization when a magnetic
force is applied with absolute steadiness to a piece of iron. It may
last for half an hour or more and amount to several per cent. of the
total magnetization. It is a true magnetic lag.

A phenomenon of magnetization of iron. It may be attributed to a sort of
internal or molecular friction, causing energy to be absorbed when iron
is magnetized. Whenever therefore the polarity or direction of
magnetization of a mass of iron is rapidly changed a considerable
expenditure of energy is required. It is attributed to the work done in
bringing the [...]

An instrument for determining the moisture in the air. One form consists
of a pair of thermometers, one of which has its bulb wrapped in cloth
which is kept moist during the observation. The evaporation is more or
less rapid according to the dryness or moisture of the air, and as the
temperature varies with this evaporation the relative [...]

An element existing under all except the most extreme artificial
conditions of pressure and cold as a gas. It is the lightest of known
substances. Atomic weight, 1; molecular weight, 2; equivalent, 1;
valency, 1; specific gravity, .0691-.0695. (Dumas & Boussingault.)
It is a dielectric of about the same resistance as air. Its specific
inductive capacity at atmospheric pressure is:
.9997 [...]

An apparatus for generating high potential difference by the escape of
steam through proper nozzles.
It consists of a boiler mounted on four glass legs or otherwise
insulated. An escape pipe terminates in a series of outlets so shaped as
to impede the escape of the steam by forcing it out of the direct
course. These jets are lined with [...]

(a) A current produced by a voltaic couple or the couple itself is
sometimes thus characterized or designated as a “hydro-electric current”
or a “hydro-electric couple.” It distinguishes them from
thermo-electric.
(b) Armstrong’s steam boiler electric machine (see Hydroelectric
Machine) is also termed a hydro-electric machine.

An apparatus for determining the presence of a concealed mass of metal.
The apparatus is variously connected. The cut shows a representative
form; a and a’ are two primary coils, each consisting of 100 meters (328
feet) of No. 32 silk covered copper wire (0.009 inch diameter) wound on
a boxwood spool ten inches in depth; b and b’ [...]

A horseshoe electro-magnet with polarized core. It is made by mounting
two bobbins of insulated wire on the ends of a permanent horseshoe
magnet. It was devised for use in Hughes’ printing telegraph, where very
quick action is required. The contact lasts only .053 second, 185
letters being transmitted per minute.

Abbreviation for “horse power.”

A horse power exerted for one hour, or the equivalent thereof. As the
horse power is a unit of activity, the horse power hour is a unit of
work or of energy. It is equal to 1,980,000 foot pounds.