Aristotle is with good reason named “the master of those who know” (Dante, _H._ iv.). He may be said to have summed up the knowledge of the ancient world, at least as far as Greece is concerned, on all subjects. If not the founder of Science any more than of Philosophy, he recapitulated so fully all that went before that he became the fountain-head and source from which all succeeding workers mainly drew. He systematised the existing materials, adding his own criticisms and observations, and illuminating the whole with the strong light of his unrivalled powers. He drew upon many authorities whose works are now lost, the leading names among them being familiar from the _Q.N._--Thales, Anaximander, Pythagoras, and the rest. The extent and variety of the material may, perhaps, best be understood from a work like Professor Burnet’s _Early Greek Philosophy_, to which reference should be made. A reasoned consecutive account will there be found of the individual contributions made to philosophy (including science) by the early Greek thinkers. Long before Aristotle’s time numerous physical theories had been propounded, and had been supported by their authors with great acuteness of argument; hardly any question had been left unasked that related to matter, motion, or mind. “We may smile, if we please, at the strange medley of childish fancy and true scientific insight.... But we shall do well to remember at the same time that even now it is just such hardy anticipations of experience that make scientific progress possible, and that nearly every one of the early inquirers ... made some permanent addition to the store of positive knowledge, besides opening up new views of the world in every direction” (_op. cit._ 29). Seneca probably possessed fuller details of the investigations and speculations of these early workers than we now do. The existing materials are contained in Professor Diels’ _Die Fragmente der Vorsokratiker_, with which his other great work, the _Doxographi Graeci_, should be compared.[21] [21] These are, of course, only for the classical scholar. The chief work of Aristotle upon which Seneca drew was the _Meteorologica_. The extent to which its subject coincided with that of the _Q.N._ may be inferred from a glance at its contents. The _Meteorologica_ is divided into four Books, arranged thus:-- I. Scope and relations of Meteorology. The four elementary bodies--earth, water, fire, air--and their relations. Celestial fires. Shooting stars. Comets. The Milky Way. Clouds. Fog. Dew. Hoar-frost. Rain. Snow. Hail. Wind. Formation of rivers. Change in land through action of rivers: effects on movements of races. II. The sea and its salinity. Theory of the winds, their varieties, positions, etc. Earthquakes and their explanation. Lightning and thunder. III. Lightning, thunder, and similar phenomena. Halo and rainbow. Mock sun and cognate appearances. Exhalation and its influence.