HYDROGEN n.
t is very abundant, being an ingredient of water and of many other substances, especially those of animal or vegetable origin. It may by produced in many ways, but is chiefly obtained by the action of acids (as sulphuric) on metals, as zinc, iron, etc. It is very inflammable, and is an ingredient of coal gas and water…
HYPERBOLIC; HYPERBOLICAL a.
nctions (Math.), certain functions which have relations to the hyperbola corresponding to those which sines, cosines, tangents, etc., have to the circle; and hence, called hyperbolic sines, hyperbolic cosines, etc. -- Hyperbolic logarithm. See Logarithm. -- Hyperbolic spiral (Math.), a spiral curve, the law of which…
ICHTHYOSAURUS n.
ct genus of marine reptiles; -- so named from their short, biconcave vertebræ, resembling those of fishes. Several species, varying in length from ten to thirty feet, are known from the Liassic, Oölitic, and Cretaceous formations.
IDEO-MOTOR a.
Applied to those actions, or muscular movements, which are automatic expressions of dominant ideas, rather than the result of distinct volitional efforts, as the act of expressing the thoughts in speech, or in writing, while the mind is occupied in the composition of the sentence. Carpenter.