1487.

Demetrius was wont to say that there was no difference between the speech and words of the foolish and ignorant, and the noises and rumblings of the wind in an inflated stomach.  Nor did he say so without reason, for he saw no difference between the parts whence the noise issued; whether their lower parts or their mouth, since one and the other were of equal use and importance.

[Footnote:  Compare Vol.  I, No. 10.]

1488.

Maestro Stefano Caponi, a physician, lives at the piscina, and has
Euclid De Ponderibus.

1489.

5th Book of Euclid.  First definition:  a part is a quantity of less magnitude than the greater magnitude when the less is contained a certain number of times in the greater.

A part properly speaking is that which may be multiplied, that is when, being multiplied by a certain number, it forms exactly the whole.  A common aggregate part ...

Second definition.  A greater magnitude is said to be a multiple of a less, when the greater is measured by the less.

By the first we define the lesser [magnitude] and by the second the greater is defined.  A part is spoken

1490.

of in relation to the whole; and all their relations lie between these two extremes, and are called multiples.

1491.

Hippocrates says that the origin of men’s sperm derives from the brain, and from the lungs and testicles of our parents, where the final decocture is made, and all the other limbs transmit their substance to this sperm by means of expiration, because there are no channels through which they might come to the sperm.

[Footnote:  The works of Hippocrates were printed first after Leonardo’s death.]

1492.

Lucretius in his third [book] ‘De Rerum Natura’.  The hands, nails and teeth were (165) the weapons of ancient man.

They also use for a standard a bunch of grass tied to a pole (167).

[Footnote:  Lucretius, de rerum natura libri VI were printed first about 1473, at Verona in 1486, at Brescia in 1495, at Venice in 1500 and in 1515, and at Florence in 1515.  The numbers 165 and 167 noted by Leonardo at the end of the two passages seem to indicate pages, but if so, none of the editions just mentioned can here be meant, nor do these numbers refer to the verses in the poems of Lucretius.]

1493.

Ammianus Marcellinus asserts that seven hundred thousand volumes of books were burnt in the siege of Alexandria in the time of Julius Cesar.

[Footnote:  Ammiani Marcellini historiarum libri qui extant XIII, published at Rome in 1474.]

1494.

Mondino says that the muscles which raise the toes are in the outward side of the thigh, and he adds that there are no muscles in the back [upper side] of the feet, because nature desired to make them light, so as to move with ease; and if they had been fleshy they would be heavier; and here experience shows ...