clearest atmosphere; and by the 10th: That shows darkest which stands out against a lighter background.
[Footnote: The quotation in this passage again cannot be verified.]
463.
OF LANDSCAPES.
The colours of the shadows in mountains at a great distance take a most lovely blue, much purer than their illuminated portions. And from this it follows that when the rock of a mountain is reddish the illuminated portions are violet (?) and the more they are lighted the more they display their proper colour.
464.
A place is most luminous when it is most remote from mountains.
On the treatment of light for views of towns (465-469).
465.
OF LIGHT AND SHADOW IN A TOWN.
When the sun is in the East and the eye is above the centre of a town, the eye will see the Southern part of the town with its roofs half in shade and half in