IX
1
2
I must now go on to speak of Streaks (watergalls, sun-dogs), which are as bright and varied as the rainbow, and commonly received by us as equally indicative of rain. No great labour need be spent in explaining them, for they are just incomplete rainbows. They have the variegated appearance of the bow, but none of its curve. They lie in a straight line. They are formed near the sun, as a rule, in a moist cloud that has begun to break up. Thus, they have the same colour as is found in the rainbow, but there is a difference in the shape, due to the corresponding difference in the clouds over which they stretch.