The Notebooks of Leonardo Da Vinci — Volume 2 eBook

This eBook from the Gutenberg Project consists of approximately 486 pages of information about The Notebooks of Leonardo Da Vinci — Volume 2.

The Notebooks of Leonardo Da Vinci — Volume 2 eBook

This eBook from the Gutenberg Project consists of approximately 486 pages of information about The Notebooks of Leonardo Da Vinci — Volume 2.

And the rocks with their various strata?

863.

Each man is always in the middle of the surface of the earth and under the zenith of his own hemisphere, and over the centre of the earth.

864.

Mem.:  That I must first show the distance of the sun from the earth; and, by means of a ray passing through a small hole into a dark chamber, detect its real size; and besides this, by means of the aqueous sphere calculate the size of the globe ...

Here it will be shown, that when the sun is in the meridian of our hemisphere [Footnote 10:  Antipodi orientali cogli occidentali.  The word Antipodes does not here bear its literal sense, but—­as we may infer from the simultaneous reference to inhabitants of the North and South—­ is used as meaning men living at a distance of 90 degrees from the zenith of the rational horizon of each observer.], the antipodes to the East and to the West, alike, and at the same time, see the sun mirrored in their waters; and the same is equally true of the arctic and antarctic poles, if indeed they are inhabited.

How to prove that the earth is a planet (865-867).

865.

That the earth is a star.

866.

In your discourse you must prove that the earth is a star much like the moon, and the glory of our universe; and then you must treat of the size of various stars, according to the authors.

867.

THE METHOD OF PROVING THAT THE EARTH IS A STAR.

First describe the eye; then show how the twinkling of a star is really in the eye and why one star should twinkle more than another, and how the rays from the stars originate in the eye; and add, that if the twinkling of the stars were really in the stars —­as it seems to be—­that this twinkling appears to be an extension as great as the diameter of the body of the star; therefore, the star being larger than the earth, this motion effected in an instant would be a rapid doubling of the size of the star.  Then prove that the surface of the air where it lies contiguous to fire, and the surface of the fire where it ends are those into which the solar rays penetrate, and transmit the images of the heavenly bodies, large when they rise, and small, when they are on the meridian.  Let a be the earth and n d m the surface of the air in contact with the sphere of fire; h f g is the orbit of the moon or, if you please, of the sun; then I say that when the sun appears on the horizon g, its rays are seen passing through the surface of the air at a slanting angle, that is o m; this is not the case at d k.  And so it passes through a greater mass of air; all of e m is a denser atmosphere.

868.

Beyond the sun and us there is darkness and so the air appears blue.

[Footnote:  Compare Vol.  I, No. 301.]

869.

PERSPECTIVE.

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The Notebooks of Leonardo Da Vinci — Volume 2 from Project Gutenberg. Public domain.