Descartes and the Rainbow
Reading the caption(1) proposed by thatsbutterbaby (via scientificillustration), I have a little suspect about the correctness. Indeed they write that the image showed the mathematics of stargazing, althought it is published in Les Météores (The Meteorology). Indeed the image is related to the explanation of the rainbows’ formation(2, 3):
Descartes first described the formation of rainbows by refraction of sunlight in raindrops in his Météores, which are part of his famous Discours de la Méthode (first published in 1637). The Cartesian explanations are largely correct as far as rainbows are concerned. He also described reflection rainbows and postulated irregular rainbows formed by irregularly-shaped droplets. The illustrations in his work were often copied by contemporary treatises. Nevertheless the Météores were often omitted in later editions of the Cartesian works.(4)
(1) The source of the caption it seems artbouillon
(2) L’arc-en-ciel
(3) Reading for example page 271-272 of Œuvres de Descartes, éd. Cousin, tome V
(4) Descartes and the Rainbow

Descartes and the Rainbow

Reading the caption(1) proposed by thatsbutterbaby (via scientificillustration), I have a little suspect about the correctness. Indeed they write that the image showed the mathematics of stargazing, althought it is published in Les Météores (The Meteorology). Indeed the image is related to the explanation of the rainbows’ formation(2, 3):

Descartes first described the formation of rainbows by refraction of sunlight in raindrops in his Météores, which are part of his famous Discours de la Méthode (first published in 1637). The Cartesian explanations are largely correct as far as rainbows are concerned. He also described reflection rainbows and postulated irregular rainbows formed by irregularly-shaped droplets. The illustrations in his work were often copied by contemporary treatises. Nevertheless the Météores were often omitted in later editions of the Cartesian works.(4)

(1) The source of the caption it seems artbouillon
(2) L’arc-en-ciel
(3) Reading for example page 271-272 of Œuvres de Descartes, éd. Cousin, tome V
(4) Descartes and the Rainbow