alue on the various
sense-organs, and to physics on the conservation of energy; but his most
original work was done in connection with acoustics in its relation to
optics; his published works include "Theory of Sound Sensations'" and
"Sensations of Tone as a Physiological Basis for the Theory of Music"
(1821-1894).

HELMONT, JEAN BAPTIST VAN, a celebrated German chemist, the father
of chemistry, born at Brussels; his early years were divided between the
study of medicine and the practice of a religious mysticism; the works of
Paracelsus stimulated his interest in chemistry and physics, and having
married a noble Brabant lady, he settled down on the family estate near
Vilvorde, where he devoted himself to scientific research; mixed up a
good deal of mysticism and alchemy with his scientific discoveries, and
made a special study of gases; he was the first to prove the
indestructibility of matter in chemical changes by utilising the balance
in analysis; he invented the word gas, first used the melting-point of
ice and the boiling-point of water as limits of a thermometric scale, and
his physiological speculations led him to regard the stomach as the seat
of the soul! (1577-1644).

HELOISE, niece of Canon Fulbert, born at Paris; celebrated for her
amour with ABELARD (q. v.); became prioress of the convent of
Argenteuil and abbess of the Paraclete, where she founded a new convent
and lived a pious life (1101-1164).

HELOISE, NOUVELLE, a romance by Rousseau.

HELOTS, slaves who formed the lowest grade of the population of
Sparta, were descendants of the original inhabitants of Laconia, or
prisoners of war; they were slaves belonging to the State, from the State
alone could they receive manumission; they were employed as tillers of
the ground, waited at meals, filled various menial offices for private
individuals, and were treated with the utmost harshness; were whipped
annually to remind them of their servile position; slaughtered when their
numbers increased too much, and were forced to exhibit themselves under
intoxication as a warning to the Spartan youth.

HELPS, SIR ARTHUR, essayist and historian, born in Surrey; for a
time held official posts in connection with the government of the day,
and finally that of Clerk to the Privy Council, in which capacity he was
brought into connection with the Queen, which led to his being appointed
editor of the "Principal Speeches and Addresses of the late Prince
Consort