“These celestial valleys present in their different contours inimitable tints of white, melting away into white, or shades lengthening themselves out without mixing over other shades.  You see, here and there, issuing from the cavernous sides of those mountains, tides of light precipitating themselves, in ingots of gold and silver, over rocks of coral.  Here it is a gloomy rock, pierced through and through, disclosing, beyond the aperture, the pure azure of the firmament; there it is an extensive strand, covered with sands of gold, stretching over the rich ground of heaven; poppy-coloured, scarlet, and green as the emerald.

“The reverberation of those western colours diffuses itself over the sea, whose azure billows it glazes with saffron and purple.  The mariners, leaning over the gunwale of the ship, admire in silence those aerial landscapes.  Sometimes this sublime spectacle presents itself to them at the hour of prayer, and seems to invite them to lift up their hearts with their voices to the heavens.  It changes every instant into forms as variable as the shades, presenting celestial colors and forms which no pencil can pretend to imitate, and no language can describe.

“Travellers who have, at various seasons, ascended to the summits of the highest mountains on the globe, never could perceive, in the clouds below them, any thing but a gray and lead-colored surface, similar to that of a lake.  The sun, notwithstanding, illuminated them with his whole light; and his rays might there combine all the laws of refraction to which our systems of physics have subjected them.  Hence not a single shade of color is employed in vain, through the universe; those celestial decorations being made for the level of the earth, their magnificent point of view taken from the habitation of man.

“These admirable concerts of lights and forms, manifest only in the lower region of the clouds the least illuminated by the sun, are produced by laws with which I am totally unacquainted.  But the whole are reducible to five colors:  yellow, a generation from white; red, a deeper shade of yellow; blue, a strong tint of red; and black, the extreme tint of blue.  This progression cannot be doubted, on observing in the morning the expansion of the light in the heavens.  You there see those five colors, with their intermediate shades, generating each other nearly in this order:  white, sulphur yellow, lemon yellow, yolk of egg yellow, orange, aurora color, poppy red, full red, carmine red, purple, violet, azure, indigo, and black.  Each color seems to be only a strong tint of that which precedes it, and a faint tint of that which follows; thus the whole together appear to be only modulations of a progression, of which white is the first term, and black the last.