Book Ii. Is a Geometrical _tour De Force_. Here, by the Methods of Pure

geometry, Archimedes investigates the positions of rest and stability of a right segment of a paraboloid of revolution floating with its base upwards or downwards (but completely above or completely below the surface) for a number of cases differing (1) according to the relation between the length of the axis of the paraboloid and the principal parameter of the generating parabola, and (2) according to the specific gravity of the solid in relation to the fluid; where the position of rest and stability is such that the axis of the solid is not vertical, the angle at which it is inclined to the vertical is fully determined.

The idea of specific gravity appears all through, though this actual term is not used. Archimedes speaks of the solid being lighter or heavier than the fluid or equally heavy with it, or when a ratio has to be expressed, he speaks of a solid the weight of which (for an equal volume) has a certain ratio to that of the fluid.

BIBLIOGRAPHY.

The editio princeps of the works of Archimedes with the commentaries of Eutocius was brought out by Hervagius (Herwagen) at Basel in 1544. D. Rivault (Paris, 1615) gave the enunciations in Greek and the proofs in Latin somewhat retouched. The Arenarius (Sandreckoner) and the Dimensio circuli with Eutocius's commentary were edited with Latin translation and notes by Wallis in 1678 (Oxford). Torelli's monumental edition (Oxford, 1792) of the Greek text of the complete works and of the commentaries of Eutocius, with a new Latin translation, remained the standard text until recent years; it is now superseded by the definitive text with Latin translation of the complete works, Eutocius's commentaries, the fragments, scholia, etc., edited by Heiberg in three volumes (Teubner, Leipzig, first edition, 1880-1; second edition, including the newly discovered Method, etc., 1910-15).

Of translations the following may be mentioned. The Aldine edition of 1558, 4to, contains the Latin translation by Commandinus of the Measurement of a Circle, On Spirals, Quadrature of the Parabola, On Conoids and Spheroids, The Sandreckoner. Isaac Barrow's version was contained in Opera Archimedis, Apollonii Pergoei conicorum libri, Theodosii Sphoerica, methodo novo illustrata et demonstrata (London, 1675). The first French version of the works was by Peyrard in two volumes (second edition, 1808). A valuable German translation, with notes, by E. Nizze, was published at Stralsund in 1824. There is a complete edition in modern notation by T. L. Heath (The Works of Archimedes, Cambridge, 1897, supplemented by The Method of Archimedes, Cambridge, 1912).

CHRONOLOGY.

(APPROXIMATE IN SOME CASES.)

B.C. 624-547 Thales 572-497 Pythagoras 500-428 Anaxagoras 470-400 / Hippocrates of Chios \ Hippias of Elis 470-380 Democritus 460-385 Theodorus of Cyrene 430-360 Archytas of Taras (Tarentum) 427-347 Plato 415-369 Theaetetus 408-355 Eudoxus of Cnidos / Leon fl. about 350 < Menaechmus | Dinostratus \ Theudius fl. 300 Euclid 310-230 Aristarchus of Samos 287-212 Archimedes 284-203 Eratosthenes 265-190 Apollonius of Perga