With respect to Ocellus Lucanus, the author of the first of these Tracts, though it is unknown at what _precise_ period he lived, yet as Archytas, in his epistle to Plato (apud Diog. Laert. viii. 80.), says “that he conversed with the descendants of Ocellus, and received from them the treatises of this philosopher On Laws, On Government, Piety, and the Generation of the Universe[2],” “we cannot be a great way off the truth,” as my worthy and very intelligent friend Mr. J. J. Welsh, in a letter to me, observes, “if we say that he lived about the time Pythagoras first opened his school in Italy, B.C. 500; which would give him for contemporaries in the _political_ world, Phalaris, Pisistratus, Crœsus, Polycrates, and Tarquin the Proud; and in the _philosophical_ world, the seven sages of Greece, Heraclitus of Ephesus, Democritus of Abdera, &c. &c.” All that is extant of his works is the treatise On the Universe[3], and a Fragment preserved by Stobæus of his treatise On Laws. And in such estimation was the former of these works held by Plato and Aristotle, that the latter, as Syrianus observes (in Aristot. Metaphys.), “has nearly taken the whole of his two books on Generation and Corruption from this work;” and that the former anxiously desired to see it, is evident from his Epistle to Archytas, of which the following is a translation: “Plato to Archytas the Tarentine, prosperity. “It is wonderful with what pleasure we received the Commentaries which came from you, and how very much we were delighted with the genius of their author. To us, indeed, he appeared to be a man worthy of his ancient progenitors. For these men are said to have been _ten thousand_[4] in number; and, according to report, were the best of all those Trojans that migrated under Laomedon. “With respect to the Commentaries by me about which you write, they are not yet finished. However, such as they are, I have sent them to you. As to guardianship, we both accord in our sentiments, so that in this particular there is no need of exhortation.” “In the Preface to the Marquis d’Argens’ French translation of this Tract, he says: ‘I have often thought that it would be much more advantageous to read what some of the Greek authors have said of the philosophy of the ancients, in order to obtain a knowledge of it, than to consult modern writers, who, though they may perhaps write well, are in general too prolix[5].’