Archimedes Texts

133
Spring-Tides. For he sagaciously and
plausibly conjectur'd that such observati
ons accurately made, would discover the
truth or erroneousness of the Cartesian
Hypothesis concerning the Ebbing and
Flowing of the Sea: which Des Cartes
ascribes to the greater pressure made upon
the Air by the Moon, and the Intercur
rent Ethereal Substance at certain times
(of the Day, and of the Lunary Moneth)
then at others. But in regard we found
the Quick-silver in the Tube to move up
and down so uncertainly, by reason, as it
seems, of accidental mutation in the Air;
I somewhat doubt whether we shall finde
the Altitude of the Quick-silver to vary
as regularly as the Experiment is ingeni
ously propos'd. The success we shall (God
permitting us to make tryal of it) acquaint
Your Lordship with; and in the mean
time take notice, that when we had occa
sion to take the Tube out of the Frame
(after it had staid there part of November
and part of December) a good Fire being
then in the room, because it was a Snowy
day, we found the Quick-silver in the
Tube to be above the upper surface of
the subjacent Mercury 29 Inches three
quarters.