The historical title, _Natural Questions_, is convenient, though, without explanation, a little misleading. The nearest rendering of the Latin form _Quaestiones Naturales_ is Physical Inquiries, or Investigations in the Domain of Physics, or, as in the title, what we should now call Physical Science. The terms Physics and Science had a very different connotation in that age and in ours. Plutarch, almost a younger contemporary of Seneca, gravely discusses in a work with a similar title such questions as Why shepherds give their sheep salt, Why horses’ hair is superior to mares’ for casting-lines, and even, Why a dog runs after a stone rather than after the person who threw it! The extent of such a title is determined pretty much by the range of topics an author decides to include. In Seneca’s case, as it happens, the branches chiefly dealt with are Astronomy and Meteorology, together with certain portions of what may be designated as Physical Geography including Seismology. Science was in that day synonymous with Philosophy, or at any rate Philosophy embraced all that could claim to be Science. Learning was homogeneous; its subdivisions had not yet been separated or differentiated. The treatise was addressed in a quasi-epistolary form to Lucilius Junior, procurator[9] of Sicily. Most of our knowledge of him is derived from Seneca, who, besides the _Q.N._, addressed to him his _Epistles_ and his tract on _Providence_. Lucilius seems to have been a _protégé_ of Seneca, and rising from the ranks under his fostering care and guidance, not only to have attained a position of influence, but also to have achieved literary distinction. His philosophical predilections were toward Epicureanism, but he was a man of high principle and character, though not exempt from dangerous temptations at various points in his career. His public labours had associated him with Sicily, and the themes of his writings, chiefly poems as it would appear, had been drawn from the same quarter. He is, not without probability, supposed to have been the author of the anonymous didactic poem _Aetna_, for long attributed to Virgil, a work which presents many interesting parallelisms to the _Q.N._ both in its science and its philosophy. Seneca’s Epistle lxxix. contains a special charge to Lucilius, who was at the time making a circuit of his province, to report the facts concerning Charybdis--Seneca knew all there was to know about Scylla--and to investigate in detail the present condition of Aetna. The letter goes on to banter Lucilius upon the inclusion of Aetna in the poem on which he was engaged--no doubt the work referred to in _Q.N._ 114, 142; cf. 167. The whole question is discussed with full knowledge by Professor Robinson Ellis in the Introduction (xxxvi-xlviii) to his edition of the _Aetna_, to which reference should be made. For other allusions to Lucilius in Seneca see, besides the _Q.N._, Epistles xix. xxvi. xxxiv. etc.