881

The question of the true and of the apparent size of the sun.

Epicurus perhaps saw the shadows cast by columns on the walls in front of them equal in diameter to the columns from which the shadows were cast; and the breadth of the shadows being parallel from beginning to end, he thought he might infer that the sun also was directly opposite to this parallel and that consequently its breadth was not greater than that of the column; not perceiving that the diminution in the shadow was insensibly slight by reason of the remoteness of the sun. If the sun were smaller than the earth, the stars on a great portion of our hemisphere would have no light, which is evidence against Epicurus who says the sun is only as large as it appears.

[Footnote: In the original the writing is across the diagram.]

Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.

Notebooks of Leonoardo da Vinci
XIV: Anatomy, Zoology and Physiology.
. . .
861,
862,
863,
864
How to prove that the earth is a planet.
865,
866,
867
The principles of astronomical perspective.
868,
869,
870,
871,
872,
873
On the luminosity of the Earth in the universal space.
874,
875,
876,
877,
878
The question of the true and of the apparent size of the sun.
879,
880,
881,
882,
883,
884
Of the nature of Sunlight.
885
Considerations as to the size of the sun.
886,
887,
888,
889,
890,
891
On the luminousity of the moon.
892,
893,
894,
895,
896,
897,
898,
899,
900,
901
. . .