Algebra and Regulae ad directionem ingenii, Descartes had established his basic program of algebraic analysis, which, even though immature, may be compared with that of François Viète. By that period his main interest, too, had already shifted from pure mathematics to natural philosophy (especially optics) and metaphysics. His studies carried out in the Netherlands during the years around 1630 first crystallized as Le Monde, ou Traité de la lumière, published posthumously in 1664, and the Dioptrique, one of the three essays added to the Discours de la méthode of 1637. The latter treatise exploited the theory of conic sections, which was excerpted partly in Beeckman's Journal in 1628–1629 (see Chapter 4, § 1), whereas the former was a writing which can be evaluated to be "the first attempt to construct an entire physical universe on mechanical foundations." ¹" /> The géométrie of 1637 - Sasaki Chikara | sdvig press