Pahlavi Texts, Part II (SBE18), E.W. West, tr. , at sacred-texts.com
1. As to the sixty-sixth question and reply, that which you ask is thus: What is this appearance 1 which is girded on the sky?
2. The reply is this, that it is a mingling of the brilliance of the sun with mist and cloud that is seen, of which it is at all times and seasons, moreover, a characteristic appearance, whereby it has become their sign above from spiritual to earthly beings.
3. That which is earthly is the water above to which its brilliance is acceptable; and the many brilliant colours (gunakân) which are formed from that much mingling 2 of brilliance and water, and are depicted (mânâkî-aîtŏ), are the one portion for appearing 3.
210:1 Reading dîdanŏîh; but the word can also be read sad-vanîh, which might stand for sad-gûnîh,' a hundred-coloured existence,' a possible term for the rainbow, but the Persian dictionaries give no nearer term than sadkas, or sadkês.
210:2 M14 has 'that mingling of many portions and few portions.'
210:3 Reading dîdanŏkŏ; but it can also be read sad-vanakŏ, a similar alternative to that in § 1.