Page:A Treatise on Painting.djvu/331

 the eye; as a finger placed near the eye will cover a large mountain far off.   is more transparent, though darker towards the extremities of its waves than in the middle.

It moves in a more oblique direction in proportion to the force of the wind which impels it.

Different kinds of smoke vary in colour, as the causes that produce them are various.

Smoke never produces determined shadows, and the extremities are lost as they recede from their primary cause. Objects behind it are less apparent in proportion to the thickness of the smoke. It is whiter nearer its origin, and bluer towards its termination.

Fire appears darker, the more smoke there is interposed between it and the eye.

Where smoke is farther distant, the objects are less confused by it.

It encumbers and dims all the landscape like a fog. Smoke is seen to issue from different places, with flames at the origin, and the most dense part of it. The tops of mountains will be more seen than the lower parts, as in a fog.   which is seen between the sun and the eye will be lighter and more transparent than any other Rh