The works of Francis Bacon, lord chancellor of England.

PHENOMENA OF THE UNIVERSE. 565
w-orthy of notice from this circumstance, that inequality movable and successive, till the water
although so great, (for it is as I have said five- regains its proper consistency and is freed from
fold,) and that not in a transient, as in the vapours the pressure: as in the waves of the sea and of
of quicksilver, but in a consistent body, it returns rivers, even after the winds have calmed, and in
without difficulty to its former orbit. all disturbed water.
Co.ntinuation of th~e Htistory of the Conjuction The same kind of inequality is evidently in the
and Expansion of MHiatter throfgh Space in' t winds also, which roll themselves together in the
same manner as the waves: neither do they resane Body.
scane Body. turn to tranquillity immediately on the cessation
Animals in swimming depress the water with of the first impetus, except that in the undulation
their hands or feet; that being depressed, rises of the air, the motion of gravity, which in water
above its natural consistency, and bears up the is joined with the motion of liberation from presbody rising upon it. But skilful swimmers can sure, does not intervene.
so balance themselves upon the water, as to keep A stone thrown sidelong on the water (as boys
themselves up for a time without moving their do in play) leaps off and repeatedly falls, and is
arms or legs; nay, to walk upright and on the struck again by the water. Swimmers when
water, and perform other feats of agility. from an eminence they leap headlong into the
Waterfowls, indeed, are webfooted, and so can water, guard against dividing it through the joinconveniently depress the water with the mem- ing of their thighs. Lastly, water struck by the
branes of their feet; but can swim better in deep hand or by the body with power, beats like a
water. ferula or any rather hard body, and causes pain.
Birds in flying beat and condense the air with And in skiffs and keels of vessels which are
their wings, but the air, (as was said of water,) guided by the force of oars, the water pushed
restoring itself to its own consistency, carries forward and borne down by the oars behind the
the bird. And birds also sometimes cut their rowers forces the skiff forward, and makes it
path with expanded wings, but retained in one move on its way, and bound onward, as a boat is
position, or now and then striking their wings moved off from the shore by the waterman's
a little and then returning to their gliding motion. pole. For the water, gathering itself behind the
And there is an analogy between winged animals, stern of the vessel and urging it into a contrary
whether feathered or not. For flies and all direction, is not the principal cause of this,
creatures of that kind have their membranes of which nevertheless arises from the pressure rewings with which they beat the air. But the laxing itself.
weakness of their wings is made up by the Air, in avoiding compression, imitates and puts
lightness of their bodies. Winged creatures are forth all the actions of a solid body; as we may
more easily borne up aloft, especially those see in the winds, which direct the courses of
which have broader wings, as the swallow, ships, overthrow houses and trees, and prostrate
though their motion is not so swift. And all them to the ground.
birds which are of considerable magnitude have The stroke that is given from a sling, hollow
more difficulty in the first stage of their flight, in and long, so as to help the compression of the air,
elevating themselves from the earth, since the air is owing to the same cause.
is of course not so deep. Boys in imitation of cannon scoop out the
wood of the alder tree and stop up each end of a
yCautdion. squirt with bits of the root of the fleur de luce,,
The motion of condensation in water, or air, or or of paper rolled up, and then shoot off the little
the like, is manifestly through striking or moving ball by means of a wooden pin, but before that
upon it. The parts of air or water, the farther touches it, the further ball is sent off with an
they are from the first stroke or impulse, the audible force by the power of the air shut up in
weaker they are struck, and the slower they give the squirt.
way; but as they are nearer, so much the more Air forcibly condensed becomes colder and
forcibly and quickly; whence it necessarily hap- seems to approach nearer the nature of water, as
pens that the anterior air, which flies with more when we raise the wind with a fan, we perceive
rapidity, comes up to the posterior air, which is the air with a hurried motion by pressing forward,
slower in its course, and so they come together. beating back again, or as when by drawing our
But since a greater condensation than is natural lips together, the breath becomes cold, or as may
results from their conjunction, the bodies of be seen in bellows.
water or air leap back and return, in order to open And when in the open air, you will find that it
and loose themselves. is much cooler when the wind is blowing than
when the air is perfectly calm.
In the generation of sounds air condensed imiThe face of water and of every fluid is uneven tates the nature of a solid body, for, as between
after agitation and perturbation, and that by an two solid bodies sound is produced by percussion,
3 B