IV. Theory of the elements (= ingredients or first principles); two active--hot and cold, two passive--dry and moist. Their effect on bodies. Cohesion, Liquefaction, Solidification, Coagulation, Fusion, Solubility, and other properties. Homogeneous and non-homogeneous bodies. Effects of temperature. Place of this work in author’s scheme. Another work that goes under Aristotle’s name, but is now generally considered spurious, is the _De Mundo_ (_the Universe_), which in part repeats the subjects of the latter part of the _Meteorology_. Seneca may also have drawn on the _De Coelo_ (_the Heavens_), whose subject covers portions of the _Q.N._ He refers more than a dozen of times to Aristotle by name, but it was not customary to refer to individual works. There are numerous instances in which Aristotle is his authority, though no specific mention of him occurs. Theophrastus, the pupil of Aristotle, and, his successor as head of the Academy, is also frequently referred to in the _Q.N._ His master bequeathed to him his library and original manuscripts, and Theophrastus was himself also a voluminous writer. Among his extant works on Science, we have treatises or tracts dealing with Fire; Winds; Stones; Signs of Rain, Wind, Storm, and Fine Weather; not to mention Colours, Odours, etc., and an extensive work on Plants and their History. His work on Perception and Percepts is said to be a chapter of a larger work on the history of philosophy. At any rate, it records and discusses the opinions of earlier writers on the subjects to which the title refers. For his further views on Physics, and the lost treatise on the subject, see Diels, _Dox. Graec._ 119 _et sqq._, and 473 _et sqq._ Aratus, who flourished about 280–270 B.C., wrote two poems (in Greek) entitled respectively _Phaenomena_,[22] an introduction to the knowledge of the constellations; and _Prognostics_, a method of forecasting the weather from astronomical phenomena. Aratus scarcely ranks as a scientific writer, but Seneca refers to his opinions on one occasion in the _Q.N._ He was apparently held in high esteem by the Romans, for he found a translator (in part) in Cicero, and an imitator in Virgil (_Georgics_). [22] It is from this poem (l. 5) that Paul quotes (Acts xvii. 28), “For we are also his offspring.” Aratus was a native of Soli in Cilicia, and therefore a compatriot of Paul.