Archimedes Texts

398
other eminent aereal alteration that might occasion the same; of
which disturbance of the Air we ought to make great account
in other accidents, and to take it for a third and accidental
cause, able to alter very much the observation of the effects de
pending on the secondary and more essential causes. And it is
not to be doubted, but that impetuous windes, continuing to
blow, for example, from the East, they shall retein the Waters
and prohibit the reflux or ebbing; whereupon the second and
third reply of the flux or tide overtaking the former, at the
hours prefixed, they will swell very high; and being thus born
up for some dayes, by the strength of the Winds, they shall rise
more than usual, making extraordinary inundations.

We ought also, (and this shall serve for a seventh Probleme)
to take notice of another cause of motion dependant on the
great abundance of the Waters of great Rivers that discharge

themselves into Seas of no great capacity, whereupon in the
Straits or Bosphori that communicate with those Seas, the Waters
are seen to run always one way: as it happeneth in the Thraci
an Bosphorus below Constantinople, where the water alwayes
runneth from the Black-Sea, towards the Propontis: For in the
said Black-Sea by reason of its shortnesse, the principal causes
of ebbing and flowing are but of small force. But, on the con
trary, very great Rivers falling into the same, those huge de
fluxions of water being to passe and disgorge themselves by the

the Straight, the ^{*}course is there very notable and alwayes to
wards the South. Where moreover we ought to take notice, that
the said Straight or Channel, albeit very narrow, is not subject
to perturbations, as the Straight of Soilla and Carybdis; for that
that hath the Black-Sea above towards the North, and the Pro
pontis, the Ægean, and the Mediterranean Seas joyned unto it,
though by a long tract towards the South; but now, as we have
observed, the Seas, though of never so great length, lying North
and South, are not much subject to ebbings and flowings; but
because the Sicilian Straight is situate between the parts of the
Mediterrane distended for a long tract or distance from West to
East, that is, according to the course of the fluxes and refluxes,
therefore in this the agitations are very great; and would be
much more violent between Hercules Pillars, in case the
Straight of Gibraltar did open lesse; and those of the Straight of
Magellanes are reported to be extraordinary violent.

The cause why,
in some narrow
Channels, we see
the Sea-waters run
alwayes one way.

This is what, for the present, cometh into my mind to say unto
you about the causes of this first period diurnal of the Tide, and
its various accidents, touching which, if you have any thing to
offer, you may let us hear it, that so we may afterwards pro
ceed to the other two periods, monethly and annual.