American Tract Society Bible Dictionary
Genesis 9:13-15 . This beautiful phenomenon is owing to the refraction of the beams of the sun in passing the drops of falling rain; the rays are separated into the prismatic colors, and then reflected from the cloud opposite to the sun and the spectator. We need not suppose that the rainbow was unknown before the flood; but God then appointed it to be the cheering seal of his covenant with the earth, which is as steadfast as the natural laws from which the rainbow springs.
These files are public domain and are a derivative of the topics are from American Tract Society Bible Dictionary published in 1859.
Rand, W. W. Entry for 'Rainbow'. American Tract Society Bible Dictionary. https://www.studylight.org/dictionaries/eng/ats/r/rainbow.html. 1859.