Archimedes Texts

Likewise, from the things demonstrated may be concluded,
that the windes, which stop a River, and blowing against the
Current, retard its course and ordinary velocity shall necessarily
amplifie the measure of the same River, and consequently shall
be, in great part, causes; or we may say, potent con-causes of
making the extraordinary inundations which Rivers use to make.
And its most certain, that as often as a strong and continual wind
shall blow against the Current of a River, and shall reduce the
water of the River to such tardity of motion, that in the time
wherein before it run five miles, it now moveth but one, such a
River will increase to five times the measure, though there should
not be added any other quantity of water; which thing indeed
hath in it something of strange, but it is most certain, for that
look what proportion the waters velocity before the winde, hath
to the velocity after the winde, and such reciprocally is the mea
sure of the same water after the winde, to the measure before
the winde; and because it hath been supposed in our case that the
velocity is diminished to a fifth part, therefore the measure shall
be increased five times more than that, which it was before.

We have also probable the cause of the inundations of Tyber,
which befel at Rome, in the time of Alexander the Sixth, & of
Clement the Seventh; which innundations came in a serene time,
and without great thaws of the Snows; which therefore much
puzzled the wits of those times. But we may with much pro
bability affirm, That the River rose to such a height and excres
cence, by the retardation of the Waters dependant on the
boistrous and constant Winds, that blew in those times, as is no
red in the memorials.

It being most manifest, that by the great abundance of Water
the Torrents may increase, and of themselves alone exorbitantly
swell the River; and having demonstrated that also without new
Water, but onely by the notable retardment the River riseth and
increaseth in measure, in proportion as the velocity decreaseth:
hence it is apparent, that each of these causes being able of it self,
and separate from the other to swell the River; when it shall
happen that both these two causes conspire the augmentation of