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.