351
2[Figure 2]
NATURAL
HISTORY.
HISTORY.
Century I.
DIg a Pit upon the Sea-ſhore, ſomewhat above the
111. High-water Mark, and ſink it as deep as the Low-
22Experiments
in Conſort,
touching the
Straining and
Paſsing of Bo-
dies one thorow
another; which
they call Per.
colation. water Mark; And as the Tide cometh in, it will fill
with Water, Freſh and Potable. This is common-
ly practiſed upon the Coaſt of Barbary, where other
Freſh Water is wanting. And Caſar knew this well,
when he was beſieged in Alexandria; for by digging
of Pits in the Sea-ſhore, he did fruſtrate the labori-
ous Works of the Enemies, which had turned the
Sea-water upon the Wells of Alexandria, and ſo ſaved his Army, being
then in Deſperation. But Caſar miſtook the cauſe; for he thought that all
Sea-ſands had Natural Springs of Freſh-water. But it is plain, that it is the
Sea-water, becauſe the Pit filleth according to the Meaſure of the Tide:
And the Sea-water paſſing or ſtraining through the Sands, leaveth the
Saltneſs.
111. High-water Mark, and ſink it as deep as the Low-
22Experiments
in Conſort,
touching the
Straining and
Paſsing of Bo-
dies one thorow
another; which
they call Per.
colation. water Mark; And as the Tide cometh in, it will fill
with Water, Freſh and Potable. This is common-
ly practiſed upon the Coaſt of Barbary, where other
Freſh Water is wanting. And Caſar knew this well,
when he was beſieged in Alexandria; for by digging
of Pits in the Sea-ſhore, he did fruſtrate the labori-
ous Works of the Enemies, which had turned the
Sea-water upon the Wells of Alexandria, and ſo ſaved his Army, being
then in Deſperation. But Caſar miſtook the cauſe; for he thought that all
Sea-ſands had Natural Springs of Freſh-water. But it is plain, that it is the
Sea-water, becauſe the Pit filleth according to the Meaſure of the Tide:
And the Sea-water paſſing or ſtraining through the Sands, leaveth the
Saltneſs.
I remember to have read, that Tryal hath been made of Salt-water
332. paſſed through Earth; through ten Veſſels, one within another, and yet it
hath not loſt his Saltneſs, as to become potable: But the ſame Man ſaith, that
(by the relation of another Salt-water drained through twenty Veſſels,
hath become freſh. This Experiment ſeemeth to croſs that other of Pits,
made by the Sea-ſide; and yet but in part, if it be true, that twenty Repeti-
tions do the effect. But it is worth the note, how poor the Imitations of
Nature are, in common courſe of Experiments, except they be led by great
Judgment, and ſome good Light of Axioms. For firſt, there is no ſmall
difference between a Paſſage of Water through twenty ſmall Veſſels, and
through ſuch a diſtance, as between the Low-water and High-water Mark.
Secondly, there is a great difference between Earth and Sand; for all Earth
hath in it a kin @e of Nitrous Salt, from which, Sand is more free: And
beſides, Earth doth not ſtrain the Water ſo finely as Sand doth. But there
is a third point, that I ſuſpect as much, or more than the other two; and
that is, that in the Experiment of Tranſmiſsion of the Sea-water into the Pits,
the Water riſeth; but in the Experiment of Tranſmiſsion of the Water, through
the Veſſels, it falleth: Now certain it is, that the Salter part of Water
332. paſſed through Earth; through ten Veſſels, one within another, and yet it
hath not loſt his Saltneſs, as to become potable: But the ſame Man ſaith, that
(by the relation of another Salt-water drained through twenty Veſſels,
hath become freſh. This Experiment ſeemeth to croſs that other of Pits,
made by the Sea-ſide; and yet but in part, if it be true, that twenty Repeti-
tions do the effect. But it is worth the note, how poor the Imitations of
Nature are, in common courſe of Experiments, except they be led by great
Judgment, and ſome good Light of Axioms. For firſt, there is no ſmall
difference between a Paſſage of Water through twenty ſmall Veſſels, and
through ſuch a diſtance, as between the Low-water and High-water Mark.
Secondly, there is a great difference between Earth and Sand; for all Earth
hath in it a kin @e of Nitrous Salt, from which, Sand is more free: And
beſides, Earth doth not ſtrain the Water ſo finely as Sand doth. But there
is a third point, that I ſuſpect as much, or more than the other two; and
that is, that in the Experiment of Tranſmiſsion of the Sea-water into the Pits,
the Water riſeth; but in the Experiment of Tranſmiſsion of the Water, through
the Veſſels, it falleth: Now certain it is, that the Salter part of Water
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