Note 2 — PART VI.
Charles Lock Eastlake translation
"Eckermann's Gespräche mit Goethe," vol. ii. p. 280. Leonardo da Vinci had made precisely the same observation. "A distant mountain will appear of a more beautiful blue in proportion as it is dark in colour. The illumined air, interposed between the eye and the dark mass, being thinner towards the summit of the mountain, will exhibit the darkness as a deeper blue and vice versâ."—Trattato della Pittura, p. 143. Elsewhere—"The air which intervenes between the eye and dark mountains becomes blue; but it does not become blue in (before) the light part, and much less in (before) the portion that is covered with snow."—p. 244.