Archimedes Texts

393
but the part C at the same time is retarded in its motion, as be
ing deprived of the progression dependant on the diurnal motion:
If we suppose, I say, a tract of Sea as long as the arch B C, we
have already seen, that its extreams shall move in the same time
with great inequality. And extreamly different would the velo
cities of a tract of Sea be that is in length a semicircle, and pla
ced in the position B C D, in regard that the extream B would
be in a most accelerate motion, and the other D, in a most slow
one; and the intermediate parts towards C, would be in a
moderate motion. And according as the said tracts of Sea shall
be shorter, they shall lesse participate of this extravagant acci
dent, of being in some hours of the day with their parts diversly
affected by velocity and tardity of motion. So that, if, as in the first
case, we see by experience that the acceleration and retardation,
though equally imparted to all the parts of the conteining Vessel,
is the cause that the water contained, fluctuates too and again, what
may we think would happen in a Vessel so admirably disposed,
that retardation and acceleration of motion is very unequally
contributed to its parts? Certainly we must needs grant that
greater and more wonderful causes of the commotions in the
Water ought to be looked for. And though it may seem im
possible to some, that in artificial Machines and Vessels we should
be able to experiment the effects of such an accident; yet ne
verthelesse it is not absolutely impossible to be done; and I have
by me the model of an Engine, in which the effect of these admi
rable commixtions of motions may be particularly observed. But
as to what concerns our present purpose, that which you may
have hitherto comprehended with your imagination may suf
fice.

SAGR. I for my own particular very well conceive that this
admirable accident ought necessarily to evene in the Straights of
Seas, and especially in those that distend themselves for a great
length from West to East; namely according to the course of
the motions of the Terrestrial Globe; and as it is in a certain
manner unthought of, and without a president among the moti
ons possible to be made by us, so it is not hard for me to believe,
that effects may be derived from the same, which are not to be i
mitated by our artificial experiments.

SALV. These things being declared, it is time that we pro
ceed to examine the particular accidents, which, together with
their diversities, are observed by experience in the ebbing and
flowing of the waters. And first we need not think it hard to

guesse whence it happeneth, that in Lakes, Pooles, and also in the
lesser Seas there is no notable flux and reflux; the which hath
two very solid reasons. The one is, that by reason of the short