No More Learning

For Telesius has well
observed, that there appears to be an original portion of light even
in the air itself,[140] although but slight and meagre, and of no use
for the most part to the eyes of men, and those of the generality
of animals; because those animals to whose senses this light is
proportioned can see by night, which does not, in all probability,
proceed from their seeing either without light or by any internal light.

Here, too, we would observe, that we at present discuss only the
wants of the senses, and their remedies; for their deceptions must be
referred to the inquiries appropriated to the senses, and sensible
objects; except that important deception, which makes them define
objects in their relation to man, and not in their relation to the
universe, and which is only corrected by universal reasoning and
philosophy. [141]

XLI. In the eighteenth rank of prerogative instances we will class the
instances of the road, which we are also wont to call itinerant and
jointed instances. They are such as indicate the gradually continued
motions of nature. This species of instances escapes rather our
observation than our senses; for men are wonderfully indolent upon
this subject, consulting nature in a desultory manner, and at periodic
intervals, when bodies have been regularly finished and completed,
and not during her work. But if any one were desirous of examining
and contemplating the talents and industry of an artificer, he would
not merely wish to see the rude materials of his art, and then his
work when finished, but rather to be present while he is at labor,
and proceeding with his work. Something of the same kind should be
done with regard to nature. For instance, if any one investigate the
vegetation of plants, he should observe from the first sowing of any
seed (which can easily be done, by pulling up every day seeds which
have been two, three, or four days in the ground, and examining them
diligently), how and when the seed begins to swell and break, and be
filled, as it were, with spirit; then how it begins to burst the bark
and push out fibres, raising itself a little at the same time, unless
the ground be very stiff; then how it pushes out these fibres, some
downward for roots, others upward for the stem, sometimes also creeping
laterally, if it find the earth open and more yielding on one side, and
the like. The same should be done in observing the hatching of eggs,
where we may easily see the process of animation and organization, and
what parts are formed of the yolk, and what of the white of the egg,
and the like. The same may be said of the inquiry into the formation
of animals from putrefaction; for it would not be so humane to inquire
into perfect and terrestrial animals, by cutting the fœtus from the
womb; but opportunities may perhaps be offered of abortions, animals
killed in hunting, and the like. Nature, therefore, must, as it were,
be watched, as being more easily observed by night than by day: for
contemplations of this kind may be considered as carried on by night,
from the minuteness and perpetual burning of our watch-light.

The same must be attempted with inanimate objects, which we have
ourselves done by inquiring into the opening of liquids by fire.
For the mode in which water expands is different from that observed
in wine, vinegar, or verjuice, and very different, again, from that
observed in milk and oil, and the like; and this was easily seen by
boiling them with slow heat, in a glass vessel, through which the
whole may be clearly perceived. But we merely mention this, intending
to treat of it more at large and more closely when we come to the
discovery of the latent process; for it should always be remembered
that we do not here treat of things themselves, but merely propose
examples. [142]

XLII. In the nineteenth rank of prerogative instances we will class
supplementary or substitutive instances, which we are also wont to call
instances of refuge. They are such as supply information, where the
senses are entirely deficient, and we therefore have recourse to them
when appropriate instances cannot be obtained. This substitution is
twofold, either by approximation or by analogy. For instance, there is
no known medium which entirely prevents the effect of the magnet in
attracting iron--neither gold, nor silver, nor stone, nor glass, wood,
water, oil, cloth, or fibrous bodies, air, flame, or the like. Yet by
accurate experiment, a medium may perhaps be found which would deaden
its effect, more than another comparatively and in degree; as, for
instance, the magnet would not perhaps attract iron through the same
thickness of gold as of air, or the same quantity of ignited as of cold
silver, and so on; for we have not ourselves made the experiment, but
it will suffice as an example. Again, there is no known body which is
not susceptible of heat, when brought near the fire; yet air becomes
warm much sooner than stone. These are examples of substitution by
approximation.

Substitution by analogy is useful, but less sure, and therefore to be
adopted with some judgment. It serves to reduce that which is not the
object of the senses to their sphere, not by the perceptible operations
of the imperceptible body, but by the consideration of some similar
perceptible body. For instance, let the subject for inquiry be the
mixture of spirits, which are invisible bodies. There appears to be
some relation between bodies and their sources or support. Now, the
source of flame seems to be oil and fat; that of air, water, and watery
substances; for flame increases over the exhalation of oil, and air
over that of water. One must therefore consider the mixture of oil and
water, which is manifest to the senses, since that of air and flame in
general escapes the senses. But oil and water mix very imperfectly by
composition or stirring, while they are exactly and nicely mixed in
herbs, blood, and the parts of animals. Something similar, therefore,
may take place in the mixture of flame and air in spirituous
substances, not bearing mixture very well by simple collision, while
they appear, however, to be well mixed in the spirits of plants and
animals.

Again, if the inquiry do not relate to perfect mixtures of spirits,
but merely to their composition, as whether they easily incorporate
with each other, or there be rather (as an example) certain winds and
exhalations, or other spiritual bodies, which do not mix with common
air, but only adhere to and float in it in globules and drops, and
are rather broken and pounded by the air, than received into, and
incorporated with it; this cannot be perceived in common air, and other
aëriform substances, on account of the rarity of the bodies, but an
image, as it were, of this process may be conceived in such liquids
as quicksilver, oil, water, and even air, when broken and dissipated
it ascends in small portions through water, and also in the thicker
kinds of smoke; lastly, in dust, raised and remaining in the air, in
all of which there is no incorporation: and the above representation
in this respect is not a bad one, if it be first diligently
investigated, whether there can be such a difference of nature between
spirituous substances, as between liquids, for then these images might
conveniently be substituted by analogy.

And although we have observed of these supplementary instances, that
information is to be derived from them, when appropriate instances are
wanting, by way of refuge, yet we would have it understood, that they
are also of great use, when the appropriate instances are at hand, in
order to confirm the information afforded by them; of which we will
speak more at length, when our subject leads us, in due course, to the
support of induction.

XLIII. In the twentieth rank of prerogative instances we will place
lancing instances, which we are also wont (but for a different reason)
to call twitching instances. We adopt the latter name, because they
twitch the understanding, and the former because they pierce nature,
whence we style them occasionally the instances of Democritus. [143]
They are such as warn the understanding of the admirable and
exquisite subtilty of nature, so that it becomes roused and awakened
to attention, observation, and proper inquiry; as, for instance,
that a little drop of ink should be drawn out into so many letters;
that silver merely gilt on its surface should be stretched to such a
length of gilt wire; that a little worm, such as you may find on the
skin, should possess both a spirit and a varied conformation of its
parts; that a little saffron should imbue a whole tub of water with
its color; that a little musk or aroma should imbue a much greater
extent of air with its perfume; that a cloud of smoke should be
raised by a little incense; that such accurate differences of sounds
as articulate words should be conveyed in all directions through the
air, and even penetrate the pores of wood and water (though they
become much weakened), that they should be, moreover, reflected, and
that with such distinctness and velocity; that light and color should
for such an extent and so rapidly pass through solid bodies, such as
glass and water, with so great and so exquisite a variety of images,
and should be refracted and reflected; that the magnet should attract
through every description of body, even the most compact; but (what
is still more wonderful) that in all these cases the action of one
should not impede that of another in a common medium, such as air;
and that there should be borne through the air, at the same time, so
many images of visible objects, so many impulses of articulation, so
many different perfumes, as of the violet, rose, etc. , besides cold and
heat, and magnetic attractions; all of them, I say, at once, without
any impediment from each other, as if each had its paths and peculiar
passage set apart for it, without infringing against or meeting each
other.

To these lancing instances, however, we are wont, not without some
advantage, to add those which we call the limits of such instances.
Thus, in the cases we have pointed out, one action does not disturb or
impede another of a different nature, yet those of a similar nature
subdue and extinguish each other; as the light of the sun does that of
the candle, the sound of a cannon that of the voice, a strong perfume a
more delicate one, a powerful heat a more gentle one, a plate of iron
between the magnet and other iron the effect of the magnet. But the
proper place for mentioning these will be also among the supports of
induction.

XLIV. We have now spoken of the instances which assist the senses,
and which are principally of service as regards information; for
information begins from the senses. But our whole labor terminates in
practice, and as the former is the beginning, so is the latter the
end of our subject. The following instances, therefore, will be those
which are chiefly useful in practice. They are comprehended in two
classes, and are seven in number. We call them all by the general name
of practical instances. Now there are two defects in practice, and as
many divisions of important instances. Practice is either deceptive or
too laborious. It is generally deceptive (especially after a diligent
examination of natures), on account of the power and actions of
bodies being ill defined and determined. Now the powers and actions
of bodies are defined and determined either by space or by time, or
by the quantity at a given period, or by the predominance of energy;
and if these four circumstances be not well and diligently considered,
the sciences may indeed be beautiful in theory, but are of no effect
in practice. We call the four instances referred to this class,
mathematical instances and instances of measure.

Practice is laborious either from the multitude of instruments, or
the bulk of matter and substances requisite for any given work. Those
instances, therefore, are valuable, which either direct practice to
that which is of most consequence to mankind, or lessen the number of
instruments or of matter to be worked upon. We assign to the three
instances relating to this class, the common name of propitious or
benevolent instances. We will now separately discuss these seven
instances, and conclude with them that part of our work which relates
to the prerogative or illustrious instances.

XLV. In the twenty-first rank of prerogative instances we will place
the instances of the rod or rule, which we are also wont to call the
instances of completion or _non ultrà_. For the powers and motions of
bodies do not act and take effect through indefinite and accidental,
but through limited and certain spaces; and it is of great importance
to practice that these should be understood and noted in every nature
which is investigated, not only to prevent deception, but to render
practice more extensive and efficient. For it is sometimes possible to
extend these powers, and bring the distance, as it were, nearer, as in
the example of telescopes.

Many powers act and take effect only by actual touch, as in the
percussion of bodies, where the one does not remove the other, unless
the impelling touch the impelled body. External applications in
medicine, as ointment and plasters, do not exercise their efficacy
except when in contact with the body. Lastly, the objects of touch and
taste only strike those senses when in contact with their organs.

Other powers act at a distance, though it be very small, of which but
few have as yet been noted, although there be more than men suspect;
this happens (to take everyday instances) when amber or jet attracts
straws, bubbles dissolve bubbles, some purgative medicines draw humors
from above, and the like. The magnetic power by which iron and the
magnet, or two magnets, are attracted together, acts within a definite
and narrow sphere, but if there be any magnetic power emanating from
the earth a little below its surface, and affecting the needle in its
polarity, it must act at a great distance.

Again, if there be any magnetic force which acts by sympathy between
the globe of the earth and heavy bodies, or between that of the moon
and the waters of the sea (as seems most probable from the particular
floods and ebbs which occur twice in the month), or between the starry
sphere and the planets, by which they are summoned and raised to their
apogees, these must all operate at very great distances. [144]

Again, some conflagrations and the kindling of flames take place
at very considerable distances with particular substances, as they
report of the naphtha of Babylon. Heat, too, insinuates itself at wide
distances, as does also cold, so that the masses of ice which are
broken off and float upon the Northern Ocean, and are borne through the
Atlantic to the coast of Canada, become perceptible by the inhabitants,
and strike them with cold from a distance. Perfumes also (though here
there appears to be always some corporeal emission) act at remarkable
distances, as is experienced by persons sailing by the coast of
Florida, or parts of Spain, where there are whole woods of lemons,
oranges, and other odoriferous plants, or rosemary and marjoram bushes,
and the like. Lastly, the rays of light and the impressions of sound
act at extensive distances.

Yet all these powers, whether acting at a small or great distance,
certainly act within definite distances, which are well ascertained
by nature, so that there is a limit depending either on the mass or
quantity of the bodies, the vigor or faintness of the powers, or the
favorable or impeding nature of the medium, all of which should be
taken into account and observed. We must also note the boundaries of
violent motions, such as missiles, projectiles, wheels and the like,
since they are also manifestly confined to certain limits.

Some motions and virtues are to be found of a directly contrary nature
to these, which act in contact but not at a distance; namely, such as
operate at a distance and not in contact, and again act with less force
at a less distance, and the reverse. Sight, for instance, is not easily
effective in contact, but requires a medium and distance; although I
remember having heard from a person deserving of credit, that in being
cured of a cataract (which was done by putting a small silver needle
within the first coat of the eye, to remove the thin pellicle of the
cataract, and force it into a corner of the eye), he had distinctly
seen the needle moving across the pupil. Still, though this may be
true, it is clear that large bodies cannot be seen well or distinctly,
unless at the vertex of a cone, where the rays from the object meet
at some distance from the eye. In old persons the eye sees better if
the object be moved a little further, and not nearer. Again, it is
certain that in projectiles the impact is not so violent at too short
a distance as a little afterward. [145] Such are the observations to be
made on the measure of motions as regards distance.

There is another measure of motion in space which must not be passed
over, not relating to progressive but spherical motion--that is,
the expansion of bodies into a greater, or their contraction into a
lesser sphere. For in our measure of this motion we must inquire what
degree of compression or extension bodies easily and readily admit of,
according to their nature, and at what point they begin to resist it,
so as at last to bear it no further--as when an inflated bladder is
compressed, it allows a certain compression of the air, but if this be
increased, the air does not suffer it, and the bladder is burst.

We have proved this by a more delicate experiment. We took a metal
bell, of a light and thin sort, such as is used for salt-cellars, and
immersed it in a basin of water, so as to carry the air contained in
its interior down with it to the bottom of the basin. We had first,
however, placed a small globe at the bottom of the basin, over which
we placed the bell. The result was, that if the globe were small
compared with the interior of the bell, the air would contract itself,
and be compressed without being forced out, but if it were too large
for the air readily to yield to it, the latter became impatient of the
pressure, raised the bell partly up, and ascended in bubbles.

To prove, also, the extension (as well as the compression) which air
admits of, we adopted the following method:--We took a glass egg, with
a small hole at one end; we drew out the air by violent suction at
this hole, and then closed the hole with the finger, immersed the egg
in water, and then removed the finger. The air being constrained by
the effort made in suction, and dilated beyond its natural state, and
therefore striving to recover and contract itself (so that if the egg
had not been immersed in water, it would have drawn in the air with a
hissing sound), now drew in a sufficient quantity of water to allow
the air to recover its former dimensions. [146]

It is well ascertained that rare bodies (such as air) admit of
considerable contraction, as has been before observed; but tangible
bodies (such as water) admit of it much less readily, and to a less
extent. We investigated the latter point by the following experiment:

We had a leaden globe made, capable of containing about two pints, wine
measure, and of tolerable thickness, so as to support considerable
pressure. We poured water into it through an aperture, which we
afterward closed with melted lead, as soon as the globe was filled with
water, so that the whole became perfectly solid. We next flattened the
two opposite sides with a heavy hammer, which necessarily caused the
water to occupy a less space, since the sphere is the solid of greatest
content; and when hammering failed from the resistance of the water,
we made use of a mill or press, till at last the water, refusing to
submit to a greater pressure, exuded like a fine dew through the solid
lead. We then computed the extent to which the original space had been
reduced, and concluded that water admitted such a degree of compression
when constrained by great violence.

The more solid, dry or compact bodies, such as stones, wood and metals,
admit of much less, and indeed scarcely any perceptible compression or
expansion, but escape by breaking, slipping forward, or other efforts;
as appears in bending wood, or steel for watch-springs, in projectiles,
hammering and many other motions, all of which, together with their
degrees, are to be observed and examined in the investigation of
nature, either to a certainty, or by estimation, or comparison, as
opportunity permits.

XLVI. In the twenty-second rank of prerogative instances we will
place the instances of the course, which we are also wont to call
water instances, borrowing our expression from the water hour-glasses
employed by the ancients instead of those with sand. They are such as
measure nature by the moments of time, as the last instances do by the
degrees of space. For all motion or natural action takes place in time,
more or less rapidly, but still in determined moments well ascertained
by nature. Even those actions which appear to take effect suddenly, and
in the twinkling of an eye (as we express it), are found to admit of
greater or less rapidity.

In the first place, then, we see that the return of the heavenly bodies
to the same place takes place in regular times, as does the flood and
ebb of the sea. The descent of heavy bodies toward the earth, and
the ascent of light bodies toward the heavenly sphere, take place in
definite times,[147] according to the nature of the body, and of the
medium through which it moves. The sailing of ships, the motions of
animals, the transmission of projectiles, all take place in times
the sums of which can be computed. With regard to heat, we see that
boys in winter bathe their hands in the flame without being burned;
and conjurers, by quick and regular movements, overturn vessels filled
with wine or water, and replace them without spilling the liquid, with
several similar instances. The compression, expansion and eruption
of several bodies, take place more or less rapidly, according to the
nature of the body and its motion, but still in definite moments.

In the explosion of several cannon at once (which are sometimes heard
at the distance of thirty miles), the sound of those nearest to the
spot is heard before that of the most distant. Even in sight (whose
action is most rapid), it is clear that a definite time is necessary
for its exertion, which is proved by certain objects being invisible
from the velocity of their motion, such as a musket-ball; for the
flight of the ball is too swift to allow an impression of its figure to
be conveyed to the sight.

This last instance, and others of a like nature, have sometimes excited
in us a most marvellous doubt, no less than whether the image of the
sky and stars is perceived as at the actual moment of its existence,
or rather a little after, and whether there is not (with regard to the
visible appearance of the heavenly bodies) a true and apparent time,
as well as a true and apparent place, which is observed by astronomers
in parallaxes. It appeared so incredible to us, that the images or
radiations of heavenly bodies could suddenly be conveyed through such
immense spaces to the sight, and it seemed that they ought rather to be
transmitted in a definite time. [148] That doubt, however (as far as
regards any great difference between the true and apparent time), was
subsequently completely set at rest, when we considered the infinite
loss and diminution of size as regards the real and apparent magnitude
of a star, occasioned by its distance, and at the same time observed
at how great a distance (at least sixty miles) bodies which are merely
white can be suddenly seen by us. For there is no doubt, that the light
of the heavenly bodies not only far surpasses the vivid appearance of
white, but even the light of any flame (with which we are acquainted)
in the vigor of its radiation. The immense velocity of the bodies
themselves, which is perceived in their diurnal motion, and has so
astonished thinking men, that they have been more ready to believe in
the motion of the earth, renders the motion of radiation from them
(marvellous as it is in its rapidity) more worthy of belief. That
which has weighed most with us, however, is, that if there were any
considerable interval of time between the reality and the appearance,
the images would often be interrupted and confused by clouds formed in
the meantime, and similar disturbances of the medium. Let this suffice
with regard to the simple measures of time.

It is not merely the absolute, but still more the relative measure of
motions and actions which must be inquired into, for this latter is
of great use and application. We perceive that the flame of firearms
is seen sooner than the sound is heard, although the ball must have
struck the air before the flame, which was behind it, could escape:
the reason of which is, that light moves with greater velocity than
sound. We perceive, also, that visible images are received by the sight
with greater rapidity than they are dismissed, and for this reason, a
violin string touched with the finger appears double or triple, because
the new image is received before the former one is dismissed. Hence,
also, rings when spinning appear globular, and a lighted torch, borne
rapidly along at night, appears to have a tail. Upon the principle of
the inequality of motion, also, Galileo attempted an explanation of
the flood and ebb of the sea, supposing the earth to move rapidly, and
the water slowly, by which means the water, after accumulating, would
at intervals fall back, as is shown in a vessel of water made to move
rapidly. He has, however, imagined this on data which cannot be granted
(namely, the earth’s motion), and besides, does not satisfactorily
account for the tide taking place every six hours.

An example of our present point (the relative measure of motion), and,
at the same time, of its remarkable use of which we have spoken, is
conspicuous in mines filled with gunpowder, where immense weights of
earth, buildings, and the like, are overthrown and prostrated by a
small quantity of powder; the reason of which is decidedly this, that
the motion of the expansion of the gunpowder is much more rapid than
that of gravity,[149] which would resist it, so that the former has
terminated before the latter has commenced. Hence, also, in missiles,
a strong blow will not carry them so far as a sharp and rapid one.
Nor could a small portion of animal spirit in animals, especially in
such vast bodies as those of the whale and elephant, have ever bent or
directed such a mass of body, were it not owing to the velocity of the
former, and the slowness of the latter in resisting its motion.

In short, this point is one of the principal foundations of the magic
experiments (of which we shall presently speak), where a small mass
of matter overcomes and regulates a much larger, if there but be an
anticipation of motion, by the velocity of one before the other is
prepared to act.

Finally, the point of the first and last should be observed in all
natural actions. Thus, in an infusion of rhubarb the purgative property
is first extracted, and then the astringent; we have experienced
something of the same kind in steeping violets in vinegar, which first
extracts the sweet and delicate odor of the flower, and then the
more earthy part, which disturbs the perfume; so that if the violets
be steeped a whole day, a much fainter perfume is extracted than if
they were steeped for a quarter of an hour only, and then taken out;
and since the odoriferous spirit in the violet is not abundant, let
other and fresh violets be steeped in the vinegar every quarter of an
hour, as many as six times, when the infusion becomes so strengthened,
that although the violets have not altogether remained there for more
than one hour and a half, there remains a most pleasing perfume, not
inferior to the flower itself, for a whole year. It must be observed,
however, that the perfume does not acquire its full strength till
about a month after the infusion. In the distillation of aromatic
plants macerated in spirits of wine, it is well known that an aqueous
and useless phlegm rises first, then water containing more of the
spirit, and, lastly, water containing more of the aroma; and many
observations of the like kind, well worthy of notice, are to be made in
distillations. But let these suffice as examples. [150]

XLVII. In the twenty-third rank of prerogative instances we will place
instances of quantity, which we are also wont to call the doses of
nature (borrowing a word from medicine). They are such as measure the
powers by the quantity of bodies, and point out the effect of the
quantity in the degree of power. And in the first place, some powers
only subsist in the universal quantity, or such as bears a relation to
the confirmation and fabric of the universe. Thus the earth is fixed,
its parts fall. The waters in the sea flow and ebb, but not in the
rivers, except by the admission of the sea. Then, again, almost all
particular powers act according to the greater or less quantity of the
body. Large masses of water are not easily rendered foul, small are.
New wine and beer become ripe and drinkable in small skins much more
readily than in large casks. If a herb be placed in a considerable
quantity of liquid, infusion takes place rather than impregnation;
if in less, the reverse. A bath, therefore, and a light sprinkling,
produce different effects on the human body. Light dew, again, never
falls, but is dissipated and incorporated with the air; thus we see
that in breathing on gems, the slight quantity of moisture, like a
small cloud in the air, is immediately dissolved. Again, a piece of
the same magnet does not attract so much iron as the whole magnet did.
There are some powers where the smallness of the quantity is of more
avail; as in boring, a sharp point pierces more readily than a blunt
one; the diamond, when pointed, makes an impression on glass, and the
like.

Here, too, we must not rest contented with a vague result, but inquire
into the exact proportion of quantity requisite for a particular
exertion of power; for one would be apt to suppose that the power bears
an exact proportion to the quantity; that if a leaden bullet of one
ounce, for instance, would fall in a given time, one of two ounces
ought to fall twice as rapidly, which is most erroneous. Nor does the
same ratio prevail in every kind of power, their difference being
considerable. The measure, therefore, must be determined by experiment,
and not by probability or conjecture.

Lastly, we must in all our investigations of nature observe what
quantity, or dose, of the body is requisite for a given effect, and
must at the same time be guarded against estimating it at too much or
too little.

XLVIII. In the twenty-fourth rank of prerogative instances we will
place wrestling instances, which we are also wont to call instances
of predominance. They are such as point out the predominance and
submission of powers compared with each other, and which of them is the
more energetic and superior, or more weak and inferior. For the motions
and effects of bodies are compounded, decomposed, and combined, no less
than the bodies themselves. We will exhibit, therefore, the principal
kinds of motions or active powers, in order that their comparative
strength, and thence a demonstration and definition of the instances in
question, may be rendered more clear.

Let the first motion be that of the resistance of matter, which exists
in every particle, and completely prevents its annihilation; so that
no conflagration, weight, pressure, violence, or length of time can
reduce even the smallest portion of matter to nothing, or prevent it
from being something, and occupying some space, and delivering itself
(whatever straits it be put to), by changing its form or place, or, if
that be impossible, remaining as it is; nor can it ever happen that it
should either be nothing or nowhere. This motion is designated by the
schools (which generally name and define everything by its effects and
inconveniences rather than by its inherent cause) by the axiom, that
two bodies cannot exist in the same place, or they call it a motion to
prevent the penetration of dimensions. It is useless to give examples
of this motion, since it exists in every body.

Let the second motion be that which we term the motion of connection,
by which bodies do not allow themselves to be separated at any point
from the contact of another body, delighting, as it were, in the
mutual connection and contact. This is called by the schools a motion
to prevent a vacuum. It takes place when water is drawn up by suction
or a syringe, the flesh by cupping, or when the water remains without
escaping from perforated jars, unless the mouth be opened to admit the
air, and innumerable instances of a like nature.

Let the third be that which we term the motion of liberty, by which
bodies strive to deliver themselves from any unnatural pressure or
tension, and to restore themselves to the dimensions suited to their
mass; and of which, also, there are innumerable examples. Thus, we have
examples of their escaping from pressure, in the water in swimming, in
the air in flying, in the water again in rowing, and in the air in the
undulation of the winds, and in springs of watches. An exact instance
of the motion of compressed air is seen in children’s popguns, which
they make by scooping out elder-branches or some such matter, and
forcing in a piece of some pulpy root or the like, at each end; then
they force the root or other pellet with a ramrod to the opposite end,
from which the lower pellet is emitted and projected with a report,
and that before it is touched by the other piece of root or pellet,
or by the ramrod. We have examples of their escape from tension, in
the motion of the air that remains in glass eggs after suction, in
strings, leather, and cloth, which recoil after tension, unless it be
long continued. The schools define this by the term of motion from the
form of the element; injudiciously enough, since this motion is to be
found not only in air, water, or fire, but in every species of solid,
as wood, iron, lead, cloth, parchment, etc. , each of which has its own
proper size, and is with difficulty stretched to any other. Since,
however, this motion of liberty is the most obvious of all, and to be
seen in an infinite number of cases, it will be as well to distinguish
it correctly and clearly; for some most carelessly confound this with
the two others of resistance and connection; namely, the freedom from
pressure with the former, and that from tension with the latter, as if
bodies when compressed yielded or expanded to prevent a penetration of
dimensions, and when stretched rebounded and contracted themselves to
prevent a vacuum. But if the air, when compressed, could be brought to
the density of water, or wood to that of stone, there would be no need
of any penetration of dimensions, and yet the compression would be much
greater than they actually admit of. So if water could be expanded till
it became as rare as air, or stone as rare as wood, there would be no
need of a vacuum, and yet the expansion would be much greater than they
actually admit of.

We do not, therefore, arrive at a penetration of dimensions or a vacuum
before the extremes of condensation and rarefaction, while the motion
we speak of stops and exerts itself much within them, and is nothing
more than a desire of bodies to preserve their specific density (or,
if it be preferred, their form), and not to desert them suddenly, but
only to change by degrees, and of their own accord. It is, however,
much more necessary to intimate to mankind (because many other points
depend upon this), that the violent motion which we call mechanical,
and Democritus (who, in explaining his primary motions, is to be ranked
even below the middling class of philosophers) termed the motion of a
blow, is nothing else than this motion of liberty, namely, a tendency
to relaxation from compression. For in all simple impulsion or flight
through the air, the body is not displaced or moved in space, until its
parts are placed in an unnatural state, and compressed by the impelling
force. When that takes place, the different parts urging the other in
succession, the whole is moved, and that with a rotatory as well as
progressive motion, in order that the parts may, by this means also,
set themselves at liberty, or more readily submit. Let this suffice for
the motion in question.

Let the fourth be that which we term the motion of matter, and which
is opposed to the last; for in the motion of liberty, bodies abhor,
reject, and avoid, a new size or volume, or any new expansion or
contraction (for these different terms have the same meaning), and
strive, with all their power, to rebound and resume their former
density; on the contrary, in the motion of matter, they are anxious
to acquire a new volume or dimension, and attempt it willingly and
rapidly, and occasionally by a most vigorous effort, as in the example
of gunpowder. The most powerful, or at least most frequent, though not
the only instruments of this motion, are heat and cold. For instance,
the air, if expanded by tension (as by suction in the glass egg),
struggles anxiously to restore itself; but if heat be applied, it
strives, on the contrary, to dilate itself, and longs for a larger
volume, regularly passing and migrating into it, as into a new form (as
it is termed); nor after a certain degree of expansion is it anxious
to return, unless it be invited to do so by the application of cold,
which is not indeed a return, but a fresh change. So also water, when
confined by compression, resists, and wishes to become as it was
before, namely, more expanded; but if there happen an intense and
continued cold, it changes itself readily, and of its own accord, into
the condensed state of ice; and if the cold be long continued, without
any intervening warmth (as in grottoes and deep caves), it is changed
into crystal or similar matter, and never resumes its form.

Let the fifth be that which we term the motion of continuity. We do
not understand by this simple and primary continuity with any other
body (for that is the motion of connection), but the continuity of
a particular body in itself; for it is most certain that all bodies
abhor a solution of continuity, some more and some less, but all
partially. In hard bodies (such as steel and glass) the resistance to
an interruption of continuity is most powerful and efficacious, while
although in liquids it appears to be faint and languid, yet it is not
altogether null, but exists in the lowest degree, and shows itself in
many experiments, such as bubbles, the round form of drops, the thin
threads which drip from roofs, the cohesion of glutinous substances,
and the like. It is most conspicuous, however, if an attempt be made to
push this separation to still smaller particles. Thus, in mortars, the
pestle produces no effect after a certain degree of contusion, water
does not penetrate small fissures, and the air itself, notwithstanding
its subtilty, does not penetrate the pores of solid vessels at once,
but only by long-continued insinuation.

Let the sixth be that which we term the motion of acquisition, or the
motion of need. [151] It is that by which bodies placed among others
of a heterogeneous and, as it were, hostile nature, if they meet with
the means or opportunity of avoiding them, and uniting themselves with
others of a more analogous nature, even when these latter are not
closely allied to them, immediately seize and, as it were, select them,
and appear to consider it as something acquired (whence we derive the
name), and to have need of these latter bodies. For instance, gold, or
any other metal in leaf, does not like the neighborhood of air; if,
therefore, they meet with any tangible and thick substance (such as the
finger, paper, or the like), they immediately adhere to it, and are
not easily torn from it. Paper, too, and cloth, and the like, do not
agree with the air, which is inherent and mixed in their pores. They
readily, therefore, imbibe water or other liquids, and get rid of the
air. Sugar, or a sponge, dipped in water or wine, and though part of
it be out of the water or wine, and at some height above it, will yet
gradually absorb them. [152]

Hence an excellent rule is derived for the opening and dissolution of
bodies; for (not to mention corrosive and strong waters, which force
their way) if a body can be found which is more adapted, suited, and
friendly to a given solid, than that with which it is by some necessity
united, the given solid immediately opens and dissolves itself to
receive the former, and excludes or removes the latter. [153] Nor is the
effect or power of this motion confined to contact, for the electric
energy (of which Gilbert and others after him have told so many fables)
is only the energy excited in a body by gentle friction, and which does
not endure the air, but prefers some tangible substance if there be any
at hand.

Let the seventh be that which we term the motion of greater
congregation, by which bodies are borne toward masses of a similar
nature, for instance, heavy bodies toward the earth, light to the
sphere of heaven. The schools termed this natural motion, by a
superficial consideration of it, because produced by no external
visible agent, which made them consider it innate in the substances; or
perhaps because it does not cease, which is little to be wondered at,
since heaven and earth are always present, while the causes and sources
of many other motions are sometimes absent and sometimes present.
They therefore called this perpetual and proper, because it is never
interrupted, but instantly takes place when the others are interrupted,
and they called the others adscititious. The former, however, is in
reality weak and slow, since it yields, and is inferior to the others
as long as they act, unless the mass of the body be great; and although
this motion have so filled men’s minds, as almost to have obscured all
others, yet they know but little about it, and commit many errors in
its estimate.

Let the eighth be that which we term the motion of lesser congregation,
by which the homogeneous parts in any body separate themselves from
the heterogeneous and unite together, and whole bodies of a similar
substance coalesce and tend toward each other, and are sometimes
congregated, attracted, and meet, from some distance; thus in milk the
cream rises after a certain time, and in wine the dregs and tartar
sink; which effects are not to be attributed to gravity and levity
only, so as to account for the rising of some parts and the sinking
of others, but much more to the desire of the homogeneous bodies to
meet and unite. This motion differs from that of need in two points:
1st, because the latter is the stimulus of a malignant and contrary
nature, while in this of which we treat (if there be no impediment or
restraint), the parts are united by their affinity, although there be
no foreign nature to create a struggle; 2dly, because the union is
closer and more select. For in the other motion, bodies which have no
great affinity unite, if they can but avoid the hostile body, while in
this, substances which are connected by a decided kindred resemblance
come together and are molded into one. It is a motion existing in all
compound bodies, and would be readily seen in each, if it were not
confined and checked by the other affections and necessities of bodies
which disturb the union.

This motion is usually confined in the three following manners: by
the torpor of the bodies; by the power of the predominating body; by
external motion. With regard to the first, it is certain that there
is more or less sluggishness in tangible bodies, and an abhorrence of
locomotion; so that unless excited they prefer remaining contented with
their actual state, to placing themselves in a better position. There
are three means of breaking through this sluggishness--heat; the active
power of a similar body; vivid and powerful motion. With regard to
the first, heat is, on this account, defined as that which separates
heterogeneous, and draws together homogeneous substances; a definition
of the Peripatetics which is justly ridiculed by Gilbert, who says it
is as if one were to define man to be that which sows wheat and plants
vineyards; being only a definition deduced from effects, and those but
partial. But it is still more to be blamed, because those effects, such
as they are, are not a peculiar property of heat, but a mere accident
(for cold, as we shall afterward show, does the same), arising from
the desire of the homogeneous parts to unite; the heat then assists
them in breaking through that sluggishness which before restrained
their desire. With regard to the assistance derived from the power of
a similar body, it is most conspicuous in the magnet when armed with
steel, for it excites in the steel a power of adhering to steel, as a
homogeneous substance, the power of the magnet breaking through the
sluggishness of the steel.
With regard to the assistance of motion,
it is seen in wooden arrows or points, which penetrate more deeply
into wood than if they were tipped with iron, from the similarity
of the substance, the swiftness of the motion breaking through the
sluggishness of the wood; of which two last experiments we have spoken
above in the aphorism on clandestine instances. [154]

The confinement of the motion of lesser congregation, which arises
from the power of the predominant body, is shown in the decomposition
of blood and urine by cold. For as long as these substances are filled
with the active spirit, which regulates and restrains each of their
component parts, as the predominant ruler of the whole, the several
different parts do not collect themselves separately on account of the
check; but as soon as that spirit has evaporated, or has been choked by
the cold, then the decomposed parts unite, according to their natural
desire. Hence it happens, that all bodies which contain a sharp spirit
(as salts and the like), last without decomposition, owing to the
permanent and durable power of the predominating and imperious spirit.

The confinement of the motion of lesser congregation, which arises from
external motion, is very evident in that agitation of bodies which
preserves them from putrefaction. For all putrefaction depends on the
congregation of the homogeneous parts, whence, by degrees, there ensues
a corruption of the first form (as it is called), and the generation of
another. For the decomposition of the original form, which is itself
the union of the homogeneous parts, precedes the putrefaction, which
prepares the way for the generation of another. This decomposition,
if not interrupted, is simple; but if there be various obstacles,
putrefactions ensue, which are the rudiments of a new generation. But
if (to come to our present point) a frequent agitation be excited by
external motion, the motion toward union (which is delicate and gentle,
and requires to be free from all external influence) is disturbed, and
ceases; which we perceive to be the case in innumerable instances.
Thus, the daily agitation or flowing of water prevents putrefaction;
winds prevent the air from being pestilent; corn turned about and
shaken in granaries continues clean: in short, everything which is
externally agitated will with difficulty rot internally.

We must not omit that union of the parts of bodies which is the
principal cause of induration and desiccation. When the spirit or
moisture, which has evaporated into spirit, has escaped from a porous
body (such as wood, bone, parchment, and the like), the thicker parts
are drawn together, and united with a greater effort, and induration
or desiccation is the consequence; and this we attribute not so much
to the motion of connection (in order to prevent a vacuum), as to this
motion of friendship and union.

Union from a distance is rare, and yet is to be met with in more
instances than are generally observed. We perceive it when one bubble
dissolves another, when medicines attract humors from a similarity of
substance, when one string moves another in unison with it on different
instruments, and the like. We are of opinion that this motion is very
prevalent also in animal spirits, but are quite ignorant of the fact.
It is, however, conspicuous in the magnet, and magnetized iron. While
speaking of the motions of the magnet, we must plainly distinguish
them, for there are four distinct powers or effects of the magnet which
should not be confounded, although the wonder and astonishment of
mankind has classed them together. 1. The attraction of the magnet to
the magnet, or of iron to the magnet, or of magnetized iron to iron.
2. Its polarity toward the north and south, and its variation. 3. Its
penetration through gold, glass, stone, and all other substances.
4. The communication of power from the mineral to iron, and from iron
to iron, without any communication of the substances. Here, however, we
only speak of the first. There is also a singular motion of attraction
between quicksilver and gold, so that the gold attracts quicksilver
even when made use of in ointment; and those who work surrounded by
the vapors of quicksilver, are wont to hold a piece of gold in their
mouths, to collect the exhalations, which would otherwise attack their
heads and bones, and this piece soon grows white. [155] Let this suffice
for the motion of lesser congregation.

Let the ninth be the magnetic motion, which, although of the nature of
that last mentioned, yet, when operating at great distances, and on
great masses, deserves a separate inquiry, especially if it neither
begin in contact, as most motions of congregation do, nor end by
bringing the substances into contact, as all do, but only raise them,
and make them swell without any further effect. For if the moon raise
the waters, or cause moist substances to swell, or if the starry
sphere attract the planets toward their apogees, or the sun confine
the planets Mercury and Venus to within a certain distance of his
mass;[156] these motions do not appear capable of being classed under
either of those of congregation, but to be, as it were, intermediately
and imperfectly congregative, and thus to form a distinct species.

Let the tenth motion be that of avoidance, or that which is opposed
to the motion of lesser congregation, by which bodies, with a kind of
antipathy, avoid and disperse, and separate themselves from, or refuse
to unite themselves with others of a hostile nature. For although this
may sometimes appear to be an accidental motion, necessarily attendant
upon that of the lesser congregation, because the homogeneous parts
cannot unite, unless the heterogeneous be first removed and excluded,
yet it is still to be classed separately,[157] and considered as a
distinct species, because, in many cases, the desire of avoidance
appears to be more marked than that of union.

It is very conspicuous in the excrements of animals, nor less, perhaps,
in objects odious to particular senses, especially the smell and
taste; for a fetid smell is rejected by the nose, so as to produce a
sympathetic motion of expulsion at the mouth of the stomach; a bitter
and rough taste is rejected by the palate or throat, so as to produce
a sympathetic concussion and shivering of the head. This motion is
visible also in other cases. Thus it is observed in some kinds of
antiperistasis, as in the middle region of the air, the cold of which
appears to be occasioned by the rejection of cold from the regions
of the heavenly bodies; and also in the heat and combustion observed
in subterranean spots, which appear to be owing to the rejection of
heat from the centre of the earth. For heat and cold, when in small
quantities, mutually destroy each other, while in larger quantities,
like armies equally matched, they remove and eject each other in
open conflict. It is said, also that cinnamon and other perfumes
retain their odor longer when placed near privies and foul places,
because they will not unite and mix with stinks. It is well known that
quicksilver, which would otherwise reunite into a complete mass, is
prevented from so doing by man’s spittle, pork lard, turpentine and
the like, from the little affinity of its parts with those substances,
so that when surrounded by them it draws itself back, and its
avoidance of these intervening obstacles is greater than its desire of
reuniting itself to its homogeneous parts; which is what they term the
mortification of quicksilver. Again, the difference in weight of oil
and water is not the only reason for their refusing to mix, but it is
also owing to the little affinity of the two; for spirits of wine,
which are lighter than oil, mix very well with water. A very remarkable
instance of the motion in question is seen in nitre, and crude bodies
of a like nature, which abhor flame, as may be observed in gunpowder,
quicksilver and gold. The avoidance of one pole of the magnet by iron
is not (as Gilbert has well observed), strictly speaking, an avoidance,
but a conformity, or attraction to a more convenient situation.

Let the eleventh motion be that of assimilation, or self-multiplication,
or simple generation, by which latter term we do not mean the simple
generation of integral bodies, such as plants or animals, but of
homogeneous bodies. By this motion homogeneous bodies convert those
which are allied to them, or at least well disposed and prepared, into
their own substance and nature. Thus flame multiplies itself over
vapors and oily substances and generates fresh flame; the air over
water and watery substances multiplies itself and generates fresh air;
the vegetable and animal spirit, over the thin particles of a watery
or oleaginous spirit contained in its food, multiplies itself and
generates fresh spirit; the solid parts of plants and animals, as the
leaf, flower, the flesh, bone and the like, each of them assimilate
some part of the juices contained in their food, and generate a
successive and daily substance. For let none rave with Paracelsus, who
(blinded by his distillations) would have it, that nutrition takes
place by mere separation, and that the eye, nose, brain and liver lie
concealed in bread and meat, the root, leaf and flower, in the juice of
the earth; asserting that just as the artist brings out a leaf, flower,
eye, nose, hand, foot and the like, from a rude mass of stone or wood
by the separation and rejection of what is superfluous; so the great
artist within us brings out our several limbs and parts by separation
and rejection. But to leave such trifling, it is most certain that
all the parts of vegetables and animals, as well the homogeneous as
organic, first of all attract those juices contained in their food,
which are nearly common, or at least not very different, and then
assimilate and convert them into their own nature. Nor does this
assimilation, or simple generation, take place in animated bodies only,
but the inanimate also participate in the same property (as we have
observed of flame and air), and that languid spirit, which is contained
in every tangible animated substance, is perpetually working upon the
coarser parts, and converting them into spirit, which afterward is
exhaled, whence ensues a diminution of weight, and a desiccation of
which we have spoken elsewhere. [158]

Nor should we, in speaking of assimilation, neglect to mention the
accretion which is usually distinguished from aliment, and which is
observed when mud grows into a mass between stones, and is converted
into a stony substance, and the scaly substance round the teeth is
converted into one no less hard than the teeth themselves; for we are
of opinion that there exists in all bodies a desire of assimilation,
as well as of uniting with homogeneous masses. Each of these powers,
however, is confined, although in different manners, and should be
diligently investigated, because they are connected with the revival
of old age. Lastly, it is worthy of observation, that in the nine
preceding motions, bodies appear to aim at the mere preservation of
their nature, while in this they attempt its propagation.

Let the twelfth motion be that of excitement, which appears to be
a species of the last, and is sometimes mentioned by us under that
name. It is, like that, a diffusive, communicative, transitive and
multiplying motion; and they agree remarkably in their effect, although
they differ in their mode of action, and in their subject matter. The
former proceeds imperiously and with authority; it orders and compels
the assimilated to be converted and changed into the assimilating
body. The latter proceeds by art, insinuation and stealth, inviting
and disposing the excited toward the nature of the exciting body. The
former both multiplies and transforms bodies and substances; thus a
greater quantity of flame, air, spirit and flesh is formed; but in
the latter, the powers only are multiplied and changed, and heat,
the magnetic power, and putrefaction, in the above instances, are
increased. Heat does not diffuse itself when heating other bodies
by any communication of the original heat, but only by exciting the
parts of the heated body to that motion which is the form of heat, and
of which we spoke in the first vintage of the nature of heat. Heat,
therefore, is excited much less rapidly and readily in stone or metal
than in air, on account of the inaptitude and sluggishness of those
bodies in acquiring that motion, so that it is probable, that there may
be some substances, toward the centre of the earth, quite incapable of
being heated, on account of their density, which may deprive them of
the spirit by which the motion of excitement is usually commenced. Thus
also the magnet creates in the iron a new disposition of its parts, and
a conformable motion, without losing any of its virtue. So the leaven
of bread, yeast, rennet and some poisons, excite and invite successive
and continued motion in dough, beer, cheese or the human body; not so
much from the power of the exciting, as the predisposition and yielding
of the excited body.

Let the thirteenth motion be that of impression, which is also a
species of motion of assimilation, and the most subtile of diffusive
motions. We have thought it right, however, to consider it as a
distinct species, on account of its remarkable difference from the
last two; for the simple motion of assimilation transforms the bodies
themselves, so that if you remove the first agent, you diminish not
the effect of those which succeed; thus, neither the first lighting
of flame, nor the first conversion into air, are of any importance to
the flame or air next generated. So, also, the motion of excitement
still continues for a considerable time after the removal of the first
agent, as in a heated body on the removal of the original heat, in the
excited iron on the removal of the magnet, and in the dough on the
removal of the leaven. But the motion of impression, although diffusive
and transitive, appears, nevertheless, to depend on the first agent,
so that upon the removal of the latter the former immediately fails
and perishes; for which reason also it takes effect in a moment, or at
least a very short space of time. We are wont to call the two former
motions the motions of the generation of Jupiter, because when born
they continue to exist; and the latter, the motion of the generation
of Saturn, because it is immediately devoured and absorbed. It may be
seen in three instances: 1, in the rays of light; 2, in the percussions
of sounds; 3, in magnetic attractions as regards communication. For,
on the removal of light, colors and all its other images disappear,
as on the cessation of the first percussion and the vibration of the
body, sound soon fails, and although sounds are agitated by the wind,
like waves, yet it is to be observed, that the same sound does not
last during the whole time of the reverberation. Thus, when a bell is
struck, the sound appears to be continued for a considerable time, and
one might easily be led into the mistake of supposing it to float and
remain in the air during the whole time, which is most erroneous. [159]
For the reverberation is not one identical sound, but the repetition
of sounds, which is made manifest by stopping and confining the
sonorous body; thus, if a bell be stopped and held tightly, so as to
be immovable, the sound fails, and there is no further reverberation,
and if a musical string be touched after the first vibration, either
with the finger (as in the harp), or a quill (as in the harpsichord),
the sound immediately ceases. If the magnet be removed the iron falls.
The moon, however, cannot be removed from the sea, nor the earth from
a heavy falling body, and we can, therefore, make no experiment upon
them; but the case is the same.

Let the fourteenth motion be that configuration or position, by
which bodies appear to desire a peculiar situation, collocation, and
configuration with others, rather than union or separation. This is
a very abstruse notion, and has not been well investigated; and, in
some instances, appears to occur almost without any cause, although
we be mistaken in supposing this to be really the case. For if it be
asked, why the heavens revolve from east to west, rather than from
west to east, or why they turn on poles situate near the Bears, rather
than round Orion or any other part of the heaven, such a question
appears to be unreasonable, since these phenomena should be received
as determinate and the objects of our experience. There are, indeed,
some ultimate and self-existing phenomena in nature, but those which
we have just mentioned are not to be referred to that class: for we
attribute them to a certain harmony and consent of the universe, which
has not yet been properly observed. But if the motion of the earth from
west to east be allowed, the same question may be put, for it must also
revolve round certain poles, and why should they be placed where they
are, rather than elsewhere? The polarity and variation of the needle
come under our present head. There is also observed in both natural and
artificial bodies, especially solids rather than fluids, a particular
collocation and position of parts, resembling hairs or fibres, which
should be diligently investigated, since, without a discovery of them,
bodies cannot be conveniently controlled or wrought upon. The eddies
observable in liquids by which, when compressed, they successively
raise different parts of their mass before they can escape, so as to
equalize the pressure, is more correctly assigned to the motion of
liberty.

Let the fifteenth motion be that of transmission or of passage, by
which the powers of bodies are more or less impeded or advanced by
the medium, according to the nature of the bodies and their effective
powers, and also according to that of the medium. For one medium is
adapted to light, another to sound, another to heat and cold, another
to magnetic action, and so on with regard to the other actions.

Let the sixteenth be that which we term the royal or political motion,
by which the predominant and governing parts of any body check,
subdue, reduce, and regulate the others, and force them to unite,
separate, stand still, move, or assume a certain position, not from any
inclination of their own, but according to a certain order, and as best
suits the convenience of the governing part, so that there is a sort
of dominion and civil government exercised by the ruling part over its
subjects. The motion is very conspicuous in the spirits of animals,
where, as long as it is in force, it tempers all the motions of the
other parts. It is found in a less degree in other bodies, as we have
observed in blood and urine, which are not decomposed until the spirit,
which mixed and retained their parts, has been emitted or extinguished.
Nor is this motion peculiar to spirits only, although in most bodies
the spirit predominates, owing to its rapid motion and penetration;
for the grosser parts predominate in denser bodies, which are not
filled with a quick and active spirit (such as exists in quicksilver
or vitriol), so that unless this check or yoke be thrown off by some
contrivance, there is no hope of any transformation of such bodies. And
let not any one suppose that we have forgotten our subject, because
we speak of predominance in this classification of motions, which is
made entirely with the view of assisting the investigation of wrestling
instances, or instances of predominance. For we do not now treat of
the general predominance of motions or powers, but of that of parts in
whole bodies, which constitutes the particular species here considered.

Let the seventeenth motion be the spontaneous motion of revolution,
by which bodies having a tendency to move, and placed in a favorable
situation, enjoy their peculiar nature, pursuing themselves and nothing
else, and seeking, as it were, to embrace themselves. For bodies seem
either to move without any limit, or to tend toward a limit, arrived at
which they either revolve according to their peculiar nature, or rest.
Those which are favorably situated, and have a tendency to motion,
move in a circle with an eternal and unlimited motion; those which
are favorably situated and abhor motion, rest. Those which are not
favorably situated move in a straight line (as their shortest path),
in order to unite with others of a congenial nature. This motion of
revolution admits of nine differences: 1, with regard to the centre
about which the bodies move; 2, the poles round which they move; 3,
the circumference or orbit relatively to its distance from the centre;
4, the velocity, or greater or less speed with which they revolve;
5, the direction of the motion as from east to west, or the reverse;
6, the deviation from a perfect circle, by spiral lines at a greater
or less distance from the centre; 7, the deviation from the circle,
by spiral lines at a greater or less distance from the poles; 8, the
greater or less distance of these spirals from each other; 9, and
lastly, the variation of the poles if they be movable; which, however,
only affects revolution when circular. The motion in question is,
according to common and long-received opinion, considered to be that
of the heavenly bodies. There exists, however, with regard to this, a
considerable dispute between some of the ancients as well as moderns,
who have attributed a motion of revolution to the earth. A much more
reasonable controversy, perhaps, exists (if it be not a matter beyond
dispute), whether the motion in question (on the hypothesis of the
earth’s being fixed) is confined to the heavens, or rather descends and
is communicated to the air and water. The rotation of missiles, as in
darts, musket-balls, and the like, we refer entirely to the motion of
liberty.

Let the eighteenth motion be that of trepidation,[160] to which (in
the sense assigned to it by astronomers) we do not give much credit;
but in our serious and general search after the tendencies of natural
bodies, this motion occurs, and appears worthy of forming a distinct
species. It is the motion of an (as it were) eternal captivity; when
bodies, for instance, being placed not altogether according to their
nature, and yet not exactly ill, constantly tremble, and are restless,
not contented with their position, and yet not daring to advance.
Such is the motion of the heart and pulse of animals, and it must
necessarily occur in all bodies which are situated in a mean state,
between conveniences and inconveniences; so that being removed from
their proper position, they strive to escape, are repulsed, and again
continue to make the attempt.

Let the nineteenth and last motion be one which can scarcely be termed
a motion, and yet is one; and which we may call the motion of repose,
or of abhorrence of motion. It is by this motion that the earth stands
by its own weight, while its extremes move toward the middle, not
to an imaginary centre, but in order to unite. It is owing to the
same tendency, that all bodies of considerable density abhor motion,
and their only tendency is not to move, which nature they preserve,
although excited and urged in a variety of ways to motion. But if they
be compelled to move, yet do they always appear anxious to recover
their former state, and to cease from motion, in which respect they
certainly appear active, and attempt it with sufficient swiftness and
rapidity, as if fatigued, and impatient of delay. We can only have a
partial representation of this tendency, because with us every tangible
substance is not only not condensed to the utmost, but even some spirit
is added, owing to the action and concocting influence of the heavenly
bodies.

We have now, therefore, exhibited the species, or simple elements of
the motions, tendencies, and active powers, which are most universal
in nature; and no small portion of natural science has been thus
sketched out. We do not, however, deny that other instances can perhaps
be added, and our divisions changed according to some more natural
order of things, and also reduced to a less number; in which respect
we do not allude to any abstract classification, as if one were to
say, that bodies desire the preservation, exaltation, propagation, or
fruition of their nature; or, that motion tends to the preservation and
benefit either of the universe (as in the case of those of resistance
and connection), or of extensive wholes, as in the case of those of
the greater congregation, revolution, and abhorrence of motion, or
of particular forms, as in the case of the others. For although such
remarks be just, yet, unless they terminate in matter and construction,
according to true definitions, they are speculative, and of little use.
In the meantime, our classification will suffice, and be of much use
in the consideration of the predominance of powers, and examining the
wrestling instances which constitute our present subject.

For of the motions here laid down, some are quite invincible, some more
powerful than others, which they confine, check, and modify; others
extend to a greater distance, others are more immediate and swift,
others strengthen, increase, and accelerate the rest.

The motion of resistance is most adamantine and invincible. We are
yet in doubt whether such be the nature of that of connection; for
we cannot with certainty determine whether there be a vacuum, either
extensive or intermixed with matter. Of one thing, however, we are
satisfied, that the reason assigned by Leucippus and Democritus for
the introduction of a vacuum (namely, that the same bodies could not
otherwise comprehend, and fill greater and less spaces) is false. For
there is clearly a folding of matter, by which it wraps and unwraps
itself in space within certain limits, without the intervention of a
vacuum. Nor is there two thousand times more of vacuum in air than in
gold, as there should be on this hypothesis; a fact demonstrated by
the very powerful energies of fluids (which would otherwise float like
fine dust _in vacuo_), and many other proofs. The other motions direct,
and are directed by each other, according to their strength, quantity,
excitement, emission, or the assistance or impediments they meet with.

For instance; some armed magnets hold and support iron of sixty times
their own weight; so far does the motion of lesser congregation
predominate over that of the greater; but if the weight be increased,
it yields. A lever of a certain strength will raise a given weight,
and so far the motion of liberty predominates over that of the greater
congregation, but if the weight be greater, the former motion yields.
A piece of leather stretched to a certain point does not break, and
so far the motion of continuity predominates over that of tension,
but if the tension be greater, the leather breaks, and the motion of
continuity yields. A certain quantity of water flows through a chink,
and so far the motion of greater congregation predominates over that
of continuity, but if the chink be smaller it yields. If a musket be
charged with ball and powdered sulphur alone, and fire be applied,
the ball is not discharged, in which case the motion of greater
congregation overcomes that of matter; but when gunpowder is used, the
motion of matter in the sulphur predominates, being assisted by that
motion, and the motion of avoidance in the nitre; and so of the rest.
For wrestling instances (which show the predominance of powers, and in
what manner and proportion they predominate and yield) must be searched
for with active and industrious diligence.

The methods and nature of this yielding must also be diligently
examined, as for instance, whether the motions completely cease, or
exert themselves, but are constrained. For in the bodies with which
we are acquainted, there is no real but an apparent rest, either in
the whole or in parts. This apparent rest is occasioned either by
equilibrium, or the absolute predominance of motions. By equilibrium,
as in the scales of the balance, which rest if the weights be equal. By
predominance, as in perforated jars, in which the water rests, and is
prevented from falling by the predominance of the motion of connection.
It is, however, to be observed (as we have said before), how far the
yielding motions exert themselves. For if a man be held stretched out
on the ground against his will, with arms and legs bound down, or
otherwise confined, and yet strive with all his power to get up, the
struggle is not the less, although ineffectual. The real state of the
case (namely, whether the yielding motion be, as it were, annihilated
by the predominance, or there be rather a continued, although an
invisible effort) will, perhaps, appear in the concurrence of motions,
although it escape our notice in their conflict. For instance: let an
experiment be made with muskets; whether a musket-ball, at its utmost
range in a straight line, or (as it is commonly called) point-blank,
strike with less force when projected upward, where the motion of the
blow is simple, than when projected downward, where the motion of
gravity concurs with the blow.

The rules of such instances of predominance as occur should be
collected: such as the following; the more general the desired
advantage is, the stronger will be the motion; the motion of
connection, for instance, which relates to the intercourse of the parts
of the universe, is more powerful than that of gravity, which relates
to the intercourse of dense bodies only. Again, the desire of a private
good does not in general prevail against that of a public one, except
where the quantities are small. Would that such were the case in civil
matters!

XLIX. In the twenty-fifth rank of prerogative instances we will place
suggesting instances; such as suggest, or point out, that which is
advantageous to mankind; for bare power and knowledge in themselves
exalt rather than enrich human nature. We must, therefore, select from
the general store such things as are most useful to mankind. We shall
have a better opportunity of discussing these when we treat of the
application to practice; besides, in the work of interpretation, we
leave room, on every subject, for the human or optative chart; for it
is a part of science to make judicious inquiries and wishes.

L. In the twenty-sixth rank of prerogative instances we will place the
generally useful instances. They are such as relate to various points,
and frequently occur, sparing by that means considerable labor and new
trials. The proper place for treating of instruments and contrivances,
will be that in which we speak of the application to practice, and the
methods of experiment. All that has hitherto been ascertained, and
made use of, will be described in the particular history of each art.
At present, we will subjoin a few general examples of the instances in
question.

Man acts, then, upon natural bodies (besides merely bringing them
together or removing them) by seven principal methods: 1, by the
exclusion of all that impedes and disturbs; 2, by compression,
extension, agitation, and the like; 3, by heat and cold; 4, by
detention in a suitable place; 5, by checking or directing motion;
6, by peculiar harmonies; 7, by a seasonable and proper alternation,
series, and succession of all these, or, at least, of some of them.

1. With regard to the first--common air, which is always at hand, and
forces its admission, as also the rays of the heavenly bodies, create
much disturbance. Whatever, therefore, tends to exclude them may
well be considered as generally useful. The substance and thickness
of vessels in which bodies are placed when prepared for operations
may be referred to this head. So also may the accurate methods of
closing vessels by consolidation, or the _lutum sapientiæ_, as the
chemists call it. The exclusion of air by means of liquids at the
extremity is also very useful, as when they pour oil on wine, or the
juices of herbs, which by spreading itself upon the top like a cover,
preserves them uninjured from the air. Powders, also, are serviceable,
for although they contain air mixed up in them, yet they ward off
the power of the mass of circumambient air, which is seen in the
preservation of grapes and other fruits in sand or flour. Wax, honey,
pitch, and other resinous bodies, are well used in order to make the
exclusion more perfect, and to remove the air and celestial influence.
We have sometimes made an experiment by placing a vessel or other
bodies in quicksilver, the most dense of all substances capable of
being poured round others. Grottoes and subterraneous caves are of
great use in keeping off the effects of the sun, and the predatory
action of air, and in the north of Germany are used for granaries.
The depositing of bodies at the bottom of water may be also mentioned
here; and I remember having heard of some bottles of wine being let
down into a deep well in order to cool them, but left there by chance,
carelessness, and forgetfulness for several years, and then taken out;
by which means the wine not only escaped becoming flat or dead, but
was much more excellent in flavor, arising (as it appears) from a more
complete mixture of its parts. But if the case require that bodies
should be sunk to the bottom of water, as in rivers or the sea, and
yet should not touch the water, nor be inclosed in sealed vessels, but
surrounded only by air, it would be right to use that vessel which has
been sometimes employed under water above ships that have sunk, in
order to enable the divers to remain below and breathe occasionally
by turns. It was of the following nature: A hollow tub of metal was
formed, and sunk so as to have its bottom parallel with the surface of
the water; it thus carried down with it to the bottom of the sea all
the air contained in the tub. It stood upon three feet (like a tripod),
being of rather less height than a man, so that, when the diver was
in want of breath, he could put his head into the hollow of the tub,
breathe, and then continue his work. We hear that some sort of boat
or vessel has now been invented, capable of carrying men some distance
under water. Any bodies, however, can easily be suspended under some
such vessel as we have mentioned, which has occasioned our remarks upon
the experiment.

Another advantage of the careful and hermetical closing of bodies is
this--not only the admission of external air is prevented (of which we
have treated), but the spirit of bodies also is prevented from making
its escape, which is an internal operation. For any one operating on
natural bodies must be certain as to their quantity, and that nothing
has evaporated or escaped, since profound alterations take place in
bodies, when art prevents the loss or escape of any portion, while
nature prevents their annihilation. With regard to this circumstance,
a false idea has prevailed (which if true would make us despair of
preserving quantity without diminution), namely, that the spirit of
bodies, and air when rarefied by a great degree of heat, cannot be so
kept in by being inclosed in any vessel as not to escape by the small
pores. Men are led into this idea by the common experiments of a cup
inverted over water, with a candle or piece of lighted paper in it,
by which the water is drawn up, and of those cups which, when heated,
draw up the flesh. For they think that in each experiment the rarefied
air escapes, and that its quantity is therefore diminished, by which
means the water or flesh rises by the motion of connection. This is,
however, most incorrect. For the air is not diminished in quantity, but
contracted in dimensions,[161] nor does this motion of the rising of
the water begin till the flame is extinguished, or the air cooled, so
that physicians place cold sponges, moistened with water, on the cups,
in order to increase their attraction. There is, therefore, no reason
why men should fear much from the ready escape of air: for although it
be true that the most solid bodies have their pores, yet neither air,
nor spirit, readily suffers itself to be rarefied to such an extreme
degree; just as water will not escape by a small chink.

2. With regard to the second of the seven above-mentioned methods, we
must especially observe, that compression and similar violence have a
most powerful effect either in producing locomotion, and other motions
of the same nature, as may be observed in engines and projectiles, or
in destroying the organic body, and those qualities, which consist
entirely in motion (for all life, and every description of flame and
ignition are destroyed by compression, which also injures and deranges
every machine); or in destroying those qualities which consist in
position and a coarse difference of parts, as in colors; for the color
of a flower when whole, differs from that it presents when bruised, and
the same may be observed of whole and powdered amber; or in tastes,
for the taste of a pear before it is ripe, and of the same pear when
bruised and softened, is different, since it becomes perceptibly
more sweet. But such violence is of little avail in the more noble
transformations and changes of homogeneous bodies, for they do not,
by such means, acquire any constantly and permanently new state, but
one that is transitory, and always struggling to return to its former
habit and freedom. It would not, however, be useless to make some
more diligent experiments with regard to this; whether, for instance,
the condensation of a perfectly homogeneous body (such as air, water,
oil, and the like) or their rarefaction, when effected by violence,
can become permanent, fixed, and, as it were, so changed, as to become
a nature. This might at first be tried by simple perseverance, and
then by means of helps and harmonies. It might readily have been
attempted (if we had but thought of it), when we condensed water (as
was mentioned above), by hammering and compression, until it burst
out. For we ought to have left the flattened globe untouched for some
days, and then to have drawn off the water, in order to try whether it
would have immediately occupied the same dimensions as it did before
the condensation. If it had not done so, either immediately, or soon
afterward, the condensation would have appeared to have been rendered
constant; if not, it would have appeared that a restitution took place,
and that the condensation had been transitory. Something of the same
kind might have been tried with the glass eggs; the egg should have
been sealed up suddenly and firmly, after a complete exhaustion of
the air, and should have been allowed to remain so for some days, and
it might then have been tried whether, on opening the aperture, the
air would be drawn in with a hissing noise, or whether as much water
would be drawn into it when immersed, as would have been drawn into it
at first, if it had not continued sealed. For it is probable (or, at
least, worth making the experiment) that this might have happened, or
might happen, because perseverance has a similar effect upon bodies
which are a little less homogeneous. A stick bent together for some
time does not rebound, which is not owing to any loss of quantity in
the wood during the time, for the same would occur (after a larger
time) in a plate of steel, which does not evaporate. If the experiment
of simple perseverance should fail, the matter should not be given up,
but other means should be employed. For it would be no small advantage,
if bodies could be endued with fixed and constant natures by violence.
Air could then be converted into water by condensation, with other
similar effects; for man is more the master of violent motions than of
any other means.

3. The third of our seven methods is referred to that great practical
engine of nature, as well as of art, cold and heat. Here, man’s power
limps, as it were, with one leg. For we possess the heat of fire, which
is infinitely more powerful and intense than that of the sun (as it
reaches us), and that of animals. But we want cold,[162] except such
as we can obtain in winter, in caverns, or by surrounding objects
with snow and ice, which, perhaps, may be compared in degree with
the noontide heat of the sun in tropical countries, increased by the
reflection of mountains and walls. For this degree of heat and cold can
be borne for a short period only by animals, yet it is nothing compared
with the heat of a burning furnace, or the corresponding degree of
cold. [163] Everything with us has a tendency to become rarefied,
dry and wasted, and nothing to become condensed or soft, except
by mixtures, and, as it were, spurious methods. Instances of cold,
therefore, should be searched for most diligently, such as may be found
by exposing bodies upon buildings in a hard frost, in subterraneous
caverns, by surrounding bodies with snow and ice in deep places
excavated for that purpose, by letting bodies down into wells, by
burying bodies in quicksilver and metals, by immersing them in streams
which petrify wood, by burying them in the earth (which the Chinese
are reported to do with their china, masses of which, made for that
purpose, are said to remain in the ground for forty or fifty years, and
to be transmitted to their heirs as a sort of artificial mine) and the
like. The condensations which take place in nature, by means of cold,
should also be investigated, that by learning their causes, they may
be introduced into the arts; such as are observed in the exudation of
marble and stones, in the dew upon the panes of glass in a room toward
morning after a frosty night, in the formation and the gathering of
vapors under the earth into water, whence spring fountains and the like.

Besides the substances which are cold to the touch, there are others
which have also the effect of cold, and condense; they appear, however,
to act only upon the bodies of animals, and scarcely any further. Of
these we have many instances, in medicines and plasters. Some condense
the flesh and tangible parts, such as astringent and inspissating
medicines, others the spirits, such as soporifics. There are two modes
of condensing the spirits, by soporifics or provocatives to sleep;
the one by calming the motion, the other by expelling the spirit. The
violet, dried roses, lettuces, and other benign or mild remedies,
by their friendly and gently cooling vapors, invite the spirits to
unite, and restrain their violent and perturbed motion. Rose-water,
for instance, applied to the nostrils in fainting fits, causes the
resolved and relaxed spirits to recover themselves, and, as it were,
cherishes them. But opiates, and the like, banish the spirits by
their malignant and hostile quality. If they be applied, therefore,
externally, the spirits immediately quit the part and no longer readily
flow into it; but if they be taken internally, their vapor, mounting
to the head, expels, in all directions, the spirits contained in the
ventricles of the brain, and since these spirits retreat, but cannot
escape, they consequently meet and are condensed, and are sometimes
completely extinguished and suffocated; although the same opiates, when
taken in moderation, by a secondary accident (the condensation which
succeeds their union), strengthen the spirits, render them more robust,
and check their useless and inflammatory motion, by which means they
contribute not a little to the cure of diseases, and the prolongation
of life.

The preparations of bodies, also, for the reception of cold should not
be omitted, such as that water a little warmed is more easily frozen
than that which is quite cold, and the like.

Moreover, since nature supplies cold so sparingly, we must act like the
apothecaries, who, when they cannot obtain any simple ingredient, take
a succedaneum, or _quid pro quo_, as they term it, such as aloes for
xylobalsamum, cassia for cinnamon. In the same manner we should look
diligently about us, to ascertain whether there may be any substitutes
for cold, that is to say, in what other manner condensation can be
effected, which is the peculiar operation of cold.