The works of Francis Bacon, lord chancellor of England.

CENT. I. NATURAL HISTORY. 7
other men would now think that they could do the like; and so go on with a further collection:
which, if the method had been exact, many would have despaired to attain by imitation. As for
his lordship's love of order, I can refer any man to his lordship's Latin book, De Augmentis Scientiarum; which, if my judgment be any thing, is written in the exactest order that I know any writing
to be. I will conclude with a usual speech of his lordship's; That this work of his Natural History is the world as God made it, and not as men have made it; for that it hath nothing of imagination.
VW. RAWLEY.
This epistle is the sanme that should have been prefixed to this book, if Ihis lordship had lived.
CENTURY I.
E2aperiments in consort, touching the straining and the water through the vessels, it falleth. Now
passing of bodies one through another; which t1/ey certain it is that this salter part of water, once
call Percolation. salted throughout, goeth to the bottom. And
DIG a pit upon the sea-shore, somewhat above therefore no marvel, if the draining of water by
the high-water mnark, and sink it as deep as the descent doth not make it fresh: besides, I do somelow-water mark; and as the tide cometh in, it what doubt, that the very dashing of the water,
will fill with water, fresh and potable. This is that cometh from the sea, is more proper to strike
commonly practised upon the coast of Barbary, off the salt part, than where the water slideth of
where other fresh water is wanting. And Caesar her own motion.
knew this well when he was besieged in Alexan- 3. It seemeth percolation, or transmission, which
dria; for by digging of pits in the sea-shore, he is commonly called straining, is a good kind of
did frustrate the laborious works of the enemies, separation, not only of thick from thin, and gross
which had turned the seawater upon the wells of from fine, but of more subtile natures; and varietl
Alexandria; and so saved his army, being then according to the body through which the transin desperation. But Cwesar mistook the cause, mission is made: as if through a woollen bag, the
for he thought that all sea-sands had natural liquor leaveth the fatness; if through sand, the
springs of fresh water: but it is plain, that it is saltness, &ce They speak of severing wine from
the sea-water; becaus the pit filleth according to water, passing it through ivy wood., or through
the measure of the tide; and seawater passing or other the like porous body; but "4 non constat."
straining through the sands, leaveth the saltness. 4. The gum of trees, which we see to be com2. I remember to have read, that trial hath been monly shining and clear, is but a fine passage or
made of salt-water passed through earth, through straining of the juice of the tree through the wood
ten vessels, one within another; and yet it hath and bark. And in like manner, Cornish dianot lost its saltness, as to become potable: but monds, and rock rubies, which are yet more rethe same man saith, that, by relation of another, splendent than gums, are the fine exudations of
salt-water drained through twenty vessels hath stone.
become fresh. This experiment seemeth to cross 5. Aristotle giveth the cause, vainly, why the
that other of pits made by the sea-side; and yet feathers of birds are more lively colours than the
but in part, if it be true that twenty repetitions hairs of beasts; for no beast hath any fine azure,
do the effect. But it is worth the note, how poor or carnation, or green hair. He saith, it is bethe imitations of nature are in common courses of cause birds are more in the beams of the sun than
experiments, except they be led by great judg- beasts; butthat is manifestly untrue; for cattle are
ment, and some good light of axioms. For first, more in the sun than birds, that live commonly in
there is no small difference between a passage of the woods, or in some covert. The true cause is,
water through twenty small vessels, and through that the excrementitious moisture of living creasuc-h a distance, as between the low-water and tures, which maketh as well the feathers in birds,
high-water mark, Secondly, there is a great dif- as the hair in beasts, passeth in birds through a
ference between earth and sand; for all earth hath finer and more delicate strainer than it doth in
in it a kind of nitrous salt, from which sand is beasts: for feathers pass through quills; and hair
more free; and besides, earth doth not strain the through skin.
water so finely as sand doth. But there is a third 6. The clarifying of liquors by adhesion, is an
point, that I suspect as much or more than the inward percolation; and is effected, when some
other; and that is, that in the experiment of trans- cleaving body is mixed and agitated with tile limission of the sea-water into the pits, the water quors; whereby the grosser part of the liquor
riseth; but in the experiment of transmission of sticks to that cleaving body; aild so the finer part?