??????????-??????????-????-??????-????????-???????-??????????René Descartes's sketch of how Most important and secondary rainbows are fashioned, Discours de la Méthode, 1637. Descartes' 1637 treatise, Discourse on Approach (Discours de la Méthode), further more Innovative this clarification. Knowing the sizing of raindrops didn't seem to have an