Chap. III.

GRECIAN.

59

thrown on their sides, some bottom upwards, and others sunk, and as Marcellus jestinglyobserved, “ his vessels were treated as buckets to draw water.”

Appius was also obliged to abandon his designs on the land side, for similar obstaclesprevented his success : the iron hands or grapples were employed here to lift men with theirarmour into the air, and then dash them against the ground. So wonderful seemed thepower of this one eminent engineer , that they were obliged to withdraw their forces, and atlast attempt to destroy the city by famine : the place was closely blockaded, and all suppliesof provisions cut off both by sea and land.

Archimedes, who was the greatest mechanic among the ancients, was born at Syracuse ,about 290 years before the Christian era, and was nearly related to Hiero, the king of thatcity. He was educated in the sciences of his native country, and afterwards travelled intoEgypt, which had been for centuries the resort of many of the Grecian philosophers.Here he remained for several years, and probably became acquainted with the combinationsof the mechanical powers, which enabled him to produce the wonderful machines heafterwards used; for in Egypt the lever was applied long before his arrival, in lifting andmoving masses of stone to heights far greater than is usually supposed. The discoveriesof Archimedes in geometry were highly important. In the two books which he wrote uponthe sphere and cylinder, he demonstrated that beautiful theorem, that the surface as wellas the solidity of any sphere is equal to two-thirds of its circumscribing cylinder, and thatthe surface of each cylindrical segment, comprehended between planes perpendicular to theaxis, is equal to the superficies of the corresponding spherical segment. In his treatiseupon the circle, he also showed that the ratio of the diameter to the circumference was as 7is to 22 ; this result he discovered by taking an arithmetical mean between the paremetersof the inscribed and circumscribed polygons.

In his treatise on conoids and spheroids, he shows the mutual relation between thesesolids, as well as to cylinders and cones of the same base and altitude. The solidity of theparabolic conoid, he found, was one-half that of the circumscribed cylinder, or three-fourths of a cone of the same base and height; and that the area of the parabola is four-thirds that of the inscribed triangle, or two-thirds that of the circumscribed parallelo-gram. He made us acquainted with the properties of the spiral curve, and the methodof drawing tangents to it: also that the sector of the spiral is one-third of the circularsector which incloses it, and consequently that a spiral, which has made one revolution, isequal to one-third of the circle in which it is comprehended.

Tlie fundamental properties of the lever are fully given in his book Dc Equiponderantibus,or Isorropica : he there proves that a balance with unequal arms will be in equilibrio if thetwo weights in the opposite scales are reciprocally proportional to the arms of the balance.

He shows also that the fulcrum sustains the whole weight, and that there is the centreof pressure or gravity, and that this centre of gravity is to be found in the parallelogram,triangle, trapezium, or parabola.

His treatise De iis qua? Vehuntur Infiuido contains the principles upon which thescience of hydrostatics is founded : he shows that when fluids are in equilibrium, eachparticle is equally pressed in every direction : he also inquired into the state of solid bodiesfloating in water. It appears singular that it should not have been previously known thatthe weight a body lost when floating in water, was only counteracted by the upwardpressure of the liquid.

Archimedes was a man of wonderful sagacity, and laid the foundation of all the sciences,the prosecution and improvement of which are the boast of the present day. He was slainby a soldier during the assault made at the taking of Syracuse , about 212 years beforeChrist. The ingenious and simple method of raising water by means of a pipe twistedround a cylinder in the form of a corkscrew, and laid in an inclined position with one endimmersed in the water, which, when made to revolve about its axis, caused the water torun out at the top, is called the Archimedian screw, and was invented by him whilst hestudied at Alexandria, in the school of the Ptolemies .

When this rich and splendid city fell into the hands of the Romans, Marcellus, viewingfrom a height its beauty and extent, is said to have shed tears. The booty found in it wasimmense, the royal treasure was carried to Rome, and to the success of Marcellus has beenattributed the subsequent degeneracy of the Romans : the statues and pictures which werecarried away from Syracuse introduced a taste for the fine arts, and led to that effeminacyof manners which brought about the ruin of the empire.

There remains some part of the temple of Minerva, one of the most ancient in Sicily ,of which Cicero gave a very minute description : he describes the doors of gold and ivory,and twenty-seven pictures it contained : it was of the Greek Doric hexastyle, and hadfourteen columns on the flank, comprising the outer ; their height, including their capital,was 28 feet 8 inches, and their diameter 6 feet 6 inches. There are also two columns be-longing to a temple of Diana; and in that portion of the city called Neapolis are theremains of a Grecian theatre, hewn, as they generally were, out of the solid rock. It hasthree ranges of seats, separated by platforms or galleries, which afforded access to them: