????? ? ??? ??? ?????? ??? ??? ? ???, ??? ????? ?? ?? ??? ???? ??? ???? ??? ??? ??? ??? ? ????.René Descartes's sketch of how Most important and secondary rainbows are shaped, Discours de la Méthode, 1637. Descartes' 1637 treatise, Discourse on Technique (Discours de la Méthode), further State-of-the-art this rationalization. Knowing that the me