Carlyle's invented style was epic poetry combined with philosophical treatise. Another influential extant Indian treatise on political philosophy is the Sukra Neeti. It includes several texts covering subjects including a medical treatise and proverbs. Aristotle wrote a treatise "On the Pythagoreans", which is no longer extant. Thomas Cajetan wrote an influential treatise on analogy. The "Second Treatise" outlines a theory of civil society. Descartes' 1637 treatise, "Discourse on Method," further advanced this explanation. Qin's major work was the "Mathematical Treatise in Nine Sections" published in 1247. He published his "Treatise on Thermodynamics" in 1897. The catalogue was published as part of his astronomical treatise the "Almagest". "A Treatise Concerning the Correction of the Donatists", justifying coercion from scripture. In 1661 he published his "Short Treatise on God". Thus this book is normally read as a positive treatise about Cyrus. It was published in "Mathematical Treatise in Nine Sections" (Qin Jiushao, 1247). John Locke discusses slavery in his "Second Treatise of Government".