An Abbe here, has shaken, if not destroyed, the theory of De Dominis,
Descartes and Newton, for explaining the phenomenon of the rainbow.
According to that theory, you know, a cone of rays issuing from the sun,
and falling on a cloud in the opposite part of the heavens, is reflected
back in the form of a smaller cone, the apex of which is the eye of the
observer: so that the eye of the observer must be in the axis of both
cones, and equally distant from every part of the bow. But he observes,
that he has repeatedly seen bows, the one end of which has been very
near to him, and the other at a very great distance. I have often
seen the same thing myself. I recollect well to have seen the end of a
rainbow between myself and a house, or between myself and a bank, not
twenty yards distant; and this repeatedly. But I never saw, what he
says he has seen, different rainbows at the same time, intersecting
each other. I never saw coexistent bows, which were not concentric
also. Again, according to the theory, if the sun is in the horizon, the
horizon intercepts the lower half of the bow, if above the horizon, that
intercepts more than the half, in proportion.
Pages:
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735