N01310:12
Thoughts for the day of rain. In two essay's
Thoughts for the day of rain. In two essay's: I. The Gospel of the rainbow. In the meditations of piety, on the appearance of the bright clouds, with the bow of God upon them. II. The Saviour with his rainbow. And the covenant which God will remember to his people in the cloudy times that are passing over them. / By Cotton Mather., D.D. ; [Seven lines of quotations]
printed by B. Green, 1712
Title page typeset from the transcription.
Modern spelling is a reading aid: the words are the author’s, only the spelling is modernized. Original shows the page as printed, with the transcription marks.
A Famous Clergy-man of Spalato, in a Book De Radijs Visus et Lucis, Written before the Beginning of the former Century, began Mathematically to describe how the Interior Bow of the Iris, is made in Round Drops of Rain, by a Refraction of the Suns Light, and One Reflection between them; and the Exterior, by Two Refractions, and Two sorts of Reflections between them, in each Drop of Water.
Descartes, (who don't use to betray his Tutors,) took the Hints from Antonius De Dominis, and went on Mathematically, and with much Demonstration, to give us a Theory of the Iris, from the Laws of Refraction, which Lucid Rays do suffer in passing through' Diaphanous Bodies. He clearly demonstrated the primary Iris, to be only, The Suns Image, reflected from the Concave Surfaces, of an Innumerable Quantity of ⟨p. iii⟩small Spherical Drops of falling Rain, with this Necessary Circumstance, that those Rays which fell on the Objects, parallel to each other, should not after One Reflection, and Two Refractions, (viz. At going into the Drop and coming out again) be Dispersed, or made to diverge, but come back again also to the Eye, parallel to each other. The Secondary Iris he supposes produced by those Rays of the Sun, which fall more obliquely, but after the same manner as before, only in these there are Two Reflections before the Suns Rays refracted a second time, and tending towards his Eye, in a parallel Position, can get out from the Aqueous Globules.
Descartes, (who don't use to betray his Tutors,) took the Hints from Antonius De Dominis, and went on Mathematically, and with much Demonstration, to give us a Theory of the Iris, from the Laws of Refraction, which Lucid Rayes do suffer in passing thro' Diaphanous Bodies. He clearly demonstrated the primary Iris, to be only, The Suns Image, reflected from the Concave Surfaces, of an Innumerable Quantity of ⟨p. iii⟩small Sphaerical Drops of falling Rain, with this Necessary Circumstance, that those Rays which fell on the Objects, parallel to each other, should not after One Reflection, and Two Refractions, (viz. At going into the Drop and coming out again) be Dispersed, or made to diverge, but come back again also to the Eye, parallel to each other. The Secondary Iris he supposes produced by those Rays of the Sun, which fall more obliquely, but after the same manner as before, only in these there are Two Reflections before the Suns Rays refracted a second time, and tending towards his Eye, in a parallel Position, can get out from the Aqueous Globules.