The Appearance of Landscapes: The Horizon Circle
Why sunlit leaves glow green in the east and dull to ash in the west
Continuing the landscape series, this leaf explains that at sunrise all the parts of plants lit from the eastern half of the sky appear a beautiful green because their leaves are transparent to the low sun. A small circle with crosshairs, drawn in the upper-right margin and labelled b, d, a, e, c in the transcription, represents the circle of the horizon and its eastern and western halves. The accompanying note contrasts the bright, transparent eastern air with the dull, ash-coloured western air, and observes that the shadows of eastern trees grow darker as the foliage thickens.
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Sunlit eastern leaves appear a most beautiful green
When the sun is in the east, all the illuminated parts of plants appear a most beautiful green. This is because the leaves lit from the eastern half of the horizon are transparent to the sun.
Eastern air bright, western air like dark ash
Within the western semicircle the greens take on a dull colour and the air is humid and turbid, the colour of dark ash, because it is not transparent like the eastern air. The eastern air is bright, and the more so the more humid it is; the shadows of eastern trees grow darker as the foliage thickens.
Diagram of the horizon circle (b, d, a, e, c)
A small circle with crosshairs is drawn in the upper-right margin, representing the circle of the horizon divided into eastern and western halves. The transcription labels it b, d, a, e, c.