Since his youth, explains Hull, Ruskin 'recorded his observations of the weather methodically, especially the blueness of the sky (of which he took measure with a cyanometer
, a device created by the French alpinist Horace-Benedict de Saussure)'.
The colors are now light blue above (where is my cyanometer? Saussure invented one, and Humboldt used it in his travels); the landscape russet and greenish, spotted with fawn-colored ploughed lands, with green pine and gray or reddish oak woods intermixed, and dark blue or slate-colored water here and there.
It is stated in the "Life of Humboldt" that he proved "that the expression, 'The ocean reflects the sky,' was a purely poetical, not a scientifically correct one, as the sea is often blue when the sky is almost totally covered with light, white clouds." He used Saussure's cyanometer even to measure the color of the sea.