A Dictionary of Greek and Roman biography and mythology. By various writers. Ed. by William Smith. Illustrated by numerous engravings on wood.

ARCHIMEDES.
translated from the Dutch in Gilbert's " Annalen
der Physik," vol. liii. p. 242. The most probable conclusion seems to be, that Archimedes had
on some occasion set fire to a ship or ships by
means of a burning mirror, and that later writers
falsely connected the circumstance with the siege
of Syracuse. (See Ersch and Gruber's Cyclop.
art. Archim. note, and Gibbon, chap. 40.)
The following additional instances of Archimedes' skill in the application of science have
been collected from various authors by Rivaltus
(who edited his works in 1615) and others.
He detected the mixture of silver in a crown
which Hiero had ordered to be made of gold, and
determined the proportions of the two metals, by
a method suggested to him by the overflowing of
the water when he stepped into a bath. When
the thought struck him he is said to have been so
much pleased that, forgetting to put on his clothes,
he ran home shouting Eip cKa, ip-ipca. The particulars of the calculation are not preserved, but it
probably depended upon a direct comparison of the
weights of certain volumes of silver and gold with
the weight and volume of the crown; the volumes
being measured, at least in the case of the crown,
by the quantity of water displaced when the mass
ývas immersed. It is not likely that Archimedes
nvas at this time acquainted with the theorems
lemonstrated in his hydrostatical treatise con-:erning the loss of weiqht of bodies immersed in
vater, since he would hardly have evinced such
ively gratification at the obvious discovery that
hey might be applied to the problem of the crown;:is delight must rather have arisen from his now
rst catching sight of a line of investigation which
id immediately to the solution of the problem
Squestion, and ultimately to the important
leorems referred to. (Vitruv. ix. 3.; Proclus.
omm. in lib. i. Eucl. ii. 3.)
He superintended the building of a ship of exaordinary size for Hiero, of which a description
given in Athenaeus (v. p. 206, D), where he is
so said to have moved it to the sea by the help
a screw. According to Proclus, this ship was
tended by Hiero as a present to Ptolemy; it may
)ssibly have been the occasion of Archimedes'
sit to Egypt.
He invented a machine called, from its form,
)chlea, and now known as the water-screw of
rchimedes, for pumping the water out of the hold
this vessel; it is said to have been also used in
)ypt by the inhabitants of the Delta in irrigating
eir lands. (Diod. i. 34; Vitruv. x. 11.) An
vestigation of the mathematical theory of the
tter screw is given in Ersch and Gruber. The
'abian historian Abulpharagius attributes to
-chimedes the raising of the dykes and bridges
ýd as defences against the overflowing of the
le. (Pope-Blount, Censura, p. 32.) Tzetzes
I Oribasius (de Mach. xxvi.) speak of his Tris1t, a machine for moving large weights; probably:ombination of pulleys, or wheels and axles. A
Iraulic organ (a musical instrument) is mentionby Tertullian (de Anima, cap. 14), but Pliny
i. 37) attributes it to Ctesibius. (See also PapM, Math. Coll. lib. 8, introd.) An apparatus
led loculus, apparently somewhat resembling the
inese puzzle, is also attributed to Archinmedes.
)rtunatianus, de Arte Metrica, p. 2684.) His
st celebrated performance was the construction
a sphere; a kind of orrery, representing the

ARCH IMEDES. 271
movements of the heavenly bodies, of which we
have no particular description. (Claudian, EpVigr.
xxi. in Sphaeram A reinmedis; Cic.Nat. Deor. ii. 35,
Tusc. Disp. i. 25; Sext. Empir. adv. Mcath. ix. 115;
Lactant. Div. Inst. ii. 5; Ov. Fast. vi. 277.)
When Syracuse was taken, Archimedes was
killed by the Roman soldiers, ignorant or careless
who he might be. The accounts of his death vary
in some particulars, but mostly agree in describing
him as intent upon a mathematical problem at the
time. He was deeply regretted by Marcellus, who
directed his burial, and befriended his surviving
relations. (Liv. xxv. 31; Valer. Max. viii. 7. ~ 7;
Plut. Marcell. 19; Cic. de fin. v. 19.) Upon his
tomb was placed the figure of a sphere inscribed
in a cylinder, in accordance with his known wish,
and in commemoration of the discovery which he
most valued. When Cicero was quaestor in Sicily
(B. c. 75) he found this tomb near one of the gates
of the city, almost hid amongst briars, and forgotten
by the Syracusans. (Tusc. Disp. v. 23.)
Of the general character of Archimedes we have
no direct account. But his apparently disinterested devotion to his friend and admirer Hiero, in
whose service he was ever ready to exercise his
ingenuity upon objects which his own taste would
not have led him to choose (for there is doubtless
some truth in what Plutarch says on this point);
the affectionate regret which he expresses for his
deceased master Conon, in writing to his surviving
friend Dositheus (to whom most of his works are
addressed); and the unaffected simplicity with
which he announces his own discoveries, seem to
afford probable grounds for a favourable estimate
of it. That his intellect was of the very highest
order is unquestionable. He possessed, in a degree
never exceeded unless by Newton, the inventive
genius which discovers new provinces of inquiry,
and finds new points of view for old and familiar
objects; the clearness of conception which is
essential to the resolution of complex phaenomena
into their constituent elements; and the power
and habit of intense and persevering thought, without which other intellectual gifts are comparatively
fruitless. (See the introd. to the treatise " De Con.
et Sphaer.") It may be noticed that he resembled
other great thinkers, in his habit of complete abstraction from outward things, when reflecting on
subjects which made considerable demands on his
mental powers. At such times he would forget to
eat his meals, and require compulsion to take him
to the bath. (Plut. 1. c.) Compare the stories of
Newton sitting great part of the day half dressed
on his bed, while composing the Principia; and of
Socrates standing a whole day and night, thinking,
on the same spot. (Plat. Symp. p. 220, c. d.) The
success of Archimedes in conquering difficulties
seems to have made the expression wrp6o'dkqa 'ApXbii'elorv proverbial. (See Cic. ad All. xiii. 28,
pro Cluent. 32.)
The following works of Archimedes have come
down to us: A treatise on Equiponderants and
Centres of Gravity, in which the theory of the
equilibrium of the straight lever is demonstrated,
both for commensurable and incommensurable
weights; and various properties of the centres of
gravity of plane surfaces bounded by three or four
straight lines, or by a straight line and a parabola,
are established.
"The Quadrature of the Parabola, in which it is
proved, that the area cut off from a parabola by