DICTIONARY OF

Index Glass 179 Initial Condensation
Index Glass. Pivoted mirror on index bar of sextant.
Index Mirror. Alternative name for an index glass.
Indiaman. Name formerly given to any large ship regularly trading to India.
Indian Spring Low Water. Datum used in Indian tides. Is below sea level by an amount
made up by sum of amplitudes of M2, S.2, K1, 01. First used by Prof. G. H. Darwin.
Indicated Horse Power. Measurement of power developed in cylinder of a reciprocating
engine as deduced from an indicator diagram.
Indicator. Any instrument that indicates mechanically. Especially applied to instrument that
graphically indicates work done by steam while in a cylinder of a reciprocating engine.
Indicator Diagram. Graph of work done by steam while in a cylinder. Produced by
mechanism incorporated in an 'Indicator'.
Indorsement. Endorsement. That which is written on the back of a document.
Induced Current. Current developed in a conductor that is near another conductor carrying
an alternating or fluctuating current. 2. Current passing through a conductor that is in the
field of I moving magnet.
Induced Draught. Artificial draught through a furnace caused by j expediting exhaust of
funnel gases; so causing a partial vacuum on escape end of furnace and stimulating flow of
air to furnace.
Induced Magnetism. Magnetism, of a ferrous substance, due to proximity of a magnet or
magnetic field.
Induction. Generation of an effect by the action of a distant cause.
Indulgence Passenger. Person given a passage in one of H.M. ships; usually on
compassionate grounds.
Inertial Navigation. A highly-refined system of Dead Reckoning navigation.
Accelerometers, or Doppler techniques, and a computer measure the distance travelled from
the original departure position.
Inferior Conjunction. Conjunction of Moon or planet occurring between Earth and Sun.
Inferior Meridian. That meridian 180° distant from a given meridian.
Inferior Planet. Either Venus or Mercury, whose orbits around Sun lie inside orbit of Earth.
In Haul. Any rope acting in a direction opposite to that of an outhaul. Particularly applied to
rope or purchase by which a jib boom, studdingsail yard, or other spar, is hauled inboard.
Inherent Vice. Inseparable property of a substance whereby it damages or destroys itself.
In Irons. Said of a sailing vessel when she is close to the wind and will not fall off on either
tack.
Initial Condensation. Conversion of a certain amount of steam into water as it enters a
cylinder. Due to temperature of cylinder being less than temperature of steam.