The Notebooks of Leonardo Da Vinci — Complete eBook

This eBook from the Gutenberg Project consists of approximately 845 pages of information about The Notebooks of Leonardo Da Vinci — Complete.

The Notebooks of Leonardo Da Vinci — Complete eBook

This eBook from the Gutenberg Project consists of approximately 845 pages of information about The Notebooks of Leonardo Da Vinci — Complete.

Observations on the stars.

914.

To see the real nature of the planets open the covering and note at the base [Footnote 4:  basa.  This probably alludes to some instrument, perhaps the Camera obscura.] one single planet, and the reflected movement of this base will show the nature of the said planet; but arrange that the base may face only one at the time.

On history of astronomy.

915.

Cicero says in [his book] De Divinatione that Astrology has been practised five hundred seventy thousand years before the Trojan war.

57000.

[Footnote:  The statement that CICERO, De Divin. ascribes the discovery of astrology to a period 57000 years before the Trojan war I believe to be quite erroneous.  According to ERNESTI, Clavis Ciceroniana, CH.  G. SCHULZ (Lexic.  Cicer.) and the edition of De Divin. by GIESE the word Astrologia occurs only twice in CICERO:  De Divin.  II, 42. Ad Chaldaeorum monstra veniamus, de quibus Eudoxus, Platonis auditor, in astrologia judicio doctissimorum hominum facile princeps, sic opinatur (id quod scriptum reliquit):  Chaldaeis in praedictione et in notatione cujusque vitae ex natali die minime esse credendum.” He then quotes the condemnatory verdict of other philosophers as to the teaching of the Chaldaeans but says nothing as to the antiquity and origin of astronomy.  CICERO further notes De oratore I, 16 that Aratus was “ignarus astrologiae” but that is all.  So far as I know the word occurs nowhere else in CICERO; and the word Astronomia he does not seem to have used at all. (H.  MULLER-STRUBING.)]

Of time and its divisions (916-918).

916.

Although time is included in the class of Continuous Quantities, being indivisible and immaterial, it does not come entirely under the head of Geometry, which represents its divisions by means of figures and bodies of infinite variety, such as are seen to be continuous in their visible and material properties.  But only with its first principles does it agree, that is with the Point and the Line; the point may be compared to an instant of time, and the line may be likened to the length of a certain quantity of time, and just as a line begins and terminates in a point, so such a space of time. begins and terminates in an instant.  And whereas a line is infinitely divisible, the divisibility of a space of time is of the same nature; and as the divisions of the line may bear a certain proportion to each other, so may the divisions of time.

[Footnote:  This passage is repeated word for word on page 190b of the same manuscript and this is accounted for by the text in Vol.  I, No. 4.  Compare also No. 1216.]

917.

Describe the nature of Time as distinguished from the Geometrical definitions.

918.

Divide an hour into 3000 parts, and this you can do with a clock by making the pendulum lighter or heavier.

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