248 HISTORY OF THE constantly moving in a circle.* He thought that the power of this circular motion kept all these heavenly hodies (which he supposed to he masses of stone) in their courses. No doctrine of Anaxagoras gave so much offence, or was considered so clear a proof of his atheism, as his opinion that the sun, the hountiful god Helios, who shines upon both mortals and immortals, was a mass of red-hot iron.t How startling- must these opinions have appeared at a time when the people were ac- customed to consider nature as pervaded by a thousand divine powers ! And yet these new doctrines rapidly gained the ascendancy, in spite of all the opposition of religion, poetry, and even the laws which were intended to protect the ancient customs and opinions. A hundred years later Anaxagoras, with his doctrine of vovq, appeared to Aristotle a sober inquirer, as compared with the wild speculators who preceded him ; £ although Aristotle was aware that his applications of his doc- trines were unsatisfactory and defective. For as Anaxagoras endea- voured to explain natural phenomena, and in this endeavour he, like other natural philosophers, extended the influence of natural causes to its utmost limits, he of course attempted to explain as much as possible by his doctrine of circular motion, and to have recourse as rarely as possible to the agency of rove. Indeed, it appears that he only intro- duced the latter, like a dens ex machina, when all other means of ex- planation failed. § 9. Although Diogenes of Apollonia (in Crete) is not equal in importance, as a philosopher, to his contemporary Anaxagoras, he is yet too considerable a writer upon physical subjects to be here passed over in silence. Without being either the disciple or the teacher, he was a contemporary, of Anaxagoras ; and in the direction of his studies he closely followed Anaximenes, expanding the main doctrines of this philosopher rather than establishing new principles of his own. He began his treatise (which was written in the Ionic dialect) with the laudable principle, " It appears to me that every one who begins a dis- course ought to state the subject with distinctness, and to make the style simple and dignified. *'§ He then laid down the principle main-
- The mathematical studies of Anaxagoras appear likewise to have referred
chief!}' to the circle. He attempted a solution of the problem of the epiadrature of the circle, and, according to Vitruvius, he instituted some inquiries concerning the optical arrangement of the stage and theatre, which also depended on properties of the circle. f fivhoc; Itawgo;. This opinion concerning the substance of the heavenly bodies was in j^reat measure founded upon the great meteoric stone which fell at yEgos Potami, on the Hellespont, in Olymp. 78, 1 ; Anaxagoras and Diogenes of Apol- lonia both spoke of this phenomenon. Boeckh Corp. Inscript. Gr. vol. ii. p. 320. J Aristot. Met. A. iii. p. 984, ed. Berol. : olov vr.Qav e£«v« vrxo i'mn xiyovrx; rohs § Aoyou tfUVTOS ao%o{Jibov oixiit //.oi %0iav iivai rhv up%nv dvaf&pijfinrnTov vrxpifcurdu, tVi 1> igftnvtiitiv awXr.v na) eipvni. Diog. Laert. vi. 81, ix. 57. Diogen. Apolloniat. Fragm., ed. F. Panzerbieter (Lipsisc, 1830), Fragm. i.
