to the human touch appears to be that of animals, and this admits of a
great variety of degrees, for the lowest (as in insects) is scarcely
perceptible, the highest scarcely equals that of the sun’s rays in
warm climates and weather, and is not so acute as to be insufferable
to the hand. It is said, however, of Constantius, and some others of
a very dry constitution and habit of body, that when attacked with
violent fevers, they became so warm as to appear almost to burn the
hand applied to them.
9. Animals become more warm by motion and exercise, wine and feasting,
venery, burning fevers, and grief.
10. In the paroxysm of intermittent fevers the patients are at first
seized with cold and shivering, but soon afterward become more heated
than at first--in burning and pestilential fevers they are hot from the
beginning.
11. Let further inquiry be made into the comparative heat of different
animals, as fishes, quadrupeds, serpents, birds, and also of the
different species, as the lion, the kite, or man; for, according to the
vulgar opinion, fishes are the least warm internally, and birds the
most, particularly doves, hawks, and ostriches.
12. Let further inquiry be made as to the comparative heat in different
parts and limbs of the same animal; for milk, blood, seed, and eggs are
moderately warm, and less hot than the outward flesh of the animal when
in motion or agitated. The degree of heat of the brain, stomach, heart,
and the rest, has not yet been equally well investigated.
13. All animals are externally cold in winter and cold weather, but are
thought to be internally warmer.
14. The heat of the heavenly bodies, even in the warmest climates and
seasons, never reaches such a pitch as to light or burn the driest wood
or straw, or even tinder without the aid of burning-glasses. It can,
however, raise vapor from moist substances.
15. Astronomers tell us that some stars are hotter than others. Mars
is considered the warmest after the Sun, then Jupiter, then Venus. The
Moon and, above all, Saturn, are considered to be cold. Among the fixed
stars Sirius is thought the warmest, then Cor Leonis or Regulus, then
the lesser Dog-star.
16. The sun gives out more heat as it approaches toward the
perpendicular or zenith, which may be supposed to be the case with the
other planets, according to their degree of heat; for instance, that
Jupiter gives out more heat when situated beneath Cancer or Leo than
when he is beneath Capricorn and Aquarius.
17. It is to be supposed that the sun and other planets give more
heat in perigee, from their approximation to the earth, than when in
apogee. But if in any country the sun should be both in its perigee
and nearer to the perpendicular at the same time, it must necessarily
give out more heat than in a country where it is also in perigee,
but situated more obliquely; so that the comparative altitude of the
planets should be observed, and their approach to or declination from
the perpendicular in different countries.
18. The sun and other planets are thought also to give out more heat in
proportion as they are nearer to the larger fixed stars, as when the
sun is in Leo he is nearer Cor Leonis, Cauda Leonis, Spica Virginis,
Sirius, and the lesser Dog-star, than when he is in Cancer, where,
however, he approaches nearer to the perpendicular. It is probable,
also, that the quarters of the heavens produce a greater heat (though
not perceptibly), in proportion as they are adorned with a greater
number of stars, particularly those of the first magnitude.
19. On the whole, the heat of the heavenly bodies is augmented in three
ways: 1. The approach to the perpendicular; 2. Proximity or their
perigee; 3. The conjunction or union of stars.
20. There is a very considerable difference between the degree of heat
in animals, and even in the rays of the heavenly bodies (as they reach
us), and the heat of the most gentle flame, and even of all ignited
substances, nay, liquids, or the air itself when unusually heated by
fire. For the flame of spirit of wine, though diffused and uncollected,
is yet able to set straw, linen, or paper on fire, which animal heat,
or that of the sun, will never accomplish without a burning-glass.
21. There are, however, many degrees of strength and weakness in flame
and ignited bodies: but no diligent inquiry has been made in this
respect, and we must, therefore, pass it hastily over. Of all flames,
that of spirits of wine appears to be the most gentle, except perhaps
the ignis fatuus, or the flashes from the perspiration of animals.
After this we should be inclined to place the flame of light and porous
vegetables, such as straw, reeds, and dried leaves; from which the
flame of hair or feathers differs but little. Then, perhaps, comes
the flame of wood, particularly that which contains but little rosin
or pitch; that of small wood, however (such as is usually tied up in
fagots), is milder than that of the trunks or roots of trees. This can
be easily tried in iron furnaces, where a fire of fagots or branches
of trees is of little service. Next follows the flame of oil, tallow,
wax, and the like oily and fat substances, which are not very violent.
But a most powerful heat is found in pitch and rosin, and a still
greater in sulphur, camphor, naphtha, saltpetre, and salts (after they
have discharged their crude matter), and in their compounds; as in
gunpowder, Greek fire (vulgarly called wild fire), and its varieties,
which possess such a stubborn heat as scarcely to be extinguished by
water.
22. We consider that the flame which results from some imperfect metals
is very strong and active; but on all these points further inquiry
should be made.
23. The flame of vivid lightning appears to exceed all the above, so as
sometimes to have melted even wrought iron into drops, which the other
flames cannot accomplish.
24. In ignited bodies there are different degrees of heat, concerning
which, also, a diligent inquiry has not been made. We consider the
faintest heat to be that of tinder, touchwood, and dry rope match,
such as is used for discharging cannon. Next follows that of ignited
charcoal or cinders, and even bricks, and the like; but the most
violent is that of ignited metals, as iron, copper, and the like.
Further inquiry, however, must be made into this also.
25. Some ignited bodies are found to be much warmer than some flames;
for instance, red hot iron is much warmer, and burns more than the
flame of spirits of wine.
26. Some bodies even not ignited, but only heated by the fire, as
boiling water, and the air confined in reverberatories, surpass in heat
many flames and ignited substances.
27. Motion increases heat,[96] as is shown in the bellows and the
blowpipe; for the harder metals are not dissolved or melted by steady
quiet fire, without the aid of the blowpipe.
28. Let an experiment be made with burning-glasses; in which respect I
have observed, that if a glass be placed at the distance of ten inches,
for instance, from the combustible object, it does not kindle or burn
it so readily, as if the glass be placed at the distance of five inches
(for instance), and be then gradually and slowly withdrawn to the
distance of ten inches. The cone and focus of the rays, however, are
the same, but the mere motion increases the effect of the heat.
29. Conflagrations, which take place with a high wind, are thought to
make greater way against than with the wind, because when the wind
slackens, the flame recoils more rapidly than it advances when the wind
is favorable.
30. Flame does not burst out or arise unless it have some hollow
space to move and exert itself in, except in the exploding flame of
gunpowder, and the like, where the compression and confinement of the
flame increase its fury.
31. The anvil becomes so hot by the hammer, that if it were a thin
plate it might probably grow red, like ignited iron by repeated
strokes. Let the experiment be tried.
32. But in ignited bodies that are porous, so as to leave room for the
fire to move itself, if its motion be prevented by strong compression,
the fire is immediately extinguished; thus it is with tinder, or the
burning snuff of a candle or lamp, or even hot charcoal or cinders;
for when they are squeezed by snuffers, or the foot, and the like, the
effect of the fire instantly ceases.
33. The approach toward a hot body increases heat in proportion to the
approximation; a similar effect to that of light, for the nearer any
object is placed toward the light, the more visible it becomes.
34. The[97] union of different heats increases heat, unless the
substances be mixed; for a large and small fire in the same spot tend
mutually to increase each other’s heat, but lukewarm water poured into
boiling water cools it.
35. The continued neighborhood of a warm body increases heat. For the
heat, which perpetually passes and emanates from it, being mixed with
that which preceded it, multiplies the whole. A fire, for instance,
does not warm a room in half an hour as much as the same fire would in
an hour. This does not apply to light, for a lamp or candle placed in
a spot gives no more light by remaining there, than it did at first.
36. The irritation of surrounding cold increases heat, as may be seen
in fires during a sharp frost. We think that this is owing not merely
to the confinement and compression of the heat (which forms a sort
of union), but also by the exasperation of it, as when the air or a
stick are violently compressed or bent, they recoil, not only to the
point they first occupied, but still further back. Let an accurate
experiment, therefore, be made with a stick, or something of the kind,
put into the flame, in order to see whether it be not sooner burned at
the sides than in the middle of it.[98]
37. There are many degrees in the susceptibility of heat. And, first,
it must be observed how much a low gentle heat changes and partially
warms even the bodies least susceptible of it. For even the heat of the
hand imparts a little warmth to a ball of lead or other metal held a
short time in it; so easily is heat transmitted and excited, without
any apparent change in the body.
38. Of all bodies that we are acquainted with, air admits and loses
heat the most readily, which is admirably seen in weather-glasses,
whose construction is as follows: Take a glass with a hollow belly, and
a thin and long neck; turn it upside down, and place it with its mouth
downward into another glass vessel containing water; the end of the
tube touching the bottom of the vessel, and the tube itself leaning a
little on the edge, so as to be fixed upright. In order to do this more
readily, let a little wax be applied to the edge, not, however, so as
to block up the orifice, lest, by preventing the air from escaping, the
motion, which we shall presently speak of, and which is very gentle and
delicate, should be impeded.
Before the first glass be inserted in the other, its upper part (the
belly) should be warmed at the fire. Then upon placing it as we have
described, the air (which was dilated by the heat), after a sufficient
time has been allowed for it to lose the additional temperature, will
restore and contract itself to the same dimensions as that of the
external or common atmosphere at the moment of immersion, and the water
will be attracted upward in the tube to a proportionate extent. A long
narrow slip of paper should be attached to the tube, divided into as
many degrees as you please. You will then perceive, as the weather
grows warmer or colder, that the air contracts itself into a narrower
space in cold weather and dilates in the warm, which will be exhibited
by the rising of the water as the air contracts itself, and its
depression as the air dilates. The sensibility of the air with regard
to heat or cold is so delicate and exquisite, that it far exceeds the
human touch, so that a ray of sunshine, the heat of the breath, and
much more, that of the hand placed on the top of the tube, immediately
causes an evident depression of the water. We think, however, that the
spirit of animals possesses a much more delicate susceptibility of heat
and cold, only that it is impeded and blunted by the grossness of their
bodies.
39. After air, we consider those bodies to be most sensible of heat,
which have been recently changed and contracted by cold, as snow and
ice; for they begin to be dissolved and melt with the first mild
weather. Next, perhaps, follows quicksilver; then greasy substances,
as oil, butter, and the like; then wood; then water; lastly, stones
and metals, which do not easily grow hot, particularly toward their
centre.[99] When heated, however, they retain their temperature for
a very long time; so that a brick or stone, or hot iron, plunged in
a basin of cold water, and kept there for a quarter of an hour or
thereabout, retains such a heat as not to admit of being touched.
40. The less massive the body is, the more readily it grows warm at the
approach of a heated body, which shows that heat with us is somewhat
averse to a tangible mass.[100]
41. Heat with regard to the human senses and touch is various and
relative, so that lukewarm water appears hot if the hand be cold, and
cold if the hand be hot.
XIV. Any one may readily see how poor we are in history, since in the
above tables, besides occasionally inserting traditions and report
instead of approved history and authentic instances (always, however,
adding some note if their credit or authority be doubtful), we are
often forced to subjoin, “Let the experiment be tried--Let further
inquiry be made.”
XV. We are wont to term the office and use of these three tables the
presenting a review of instances to the understanding; and when this
has been done, induction itself is to be brought into action. For on an
individual review of all the instances a nature is to be found, such
as always to be present and absent with the given nature, to increase
and decrease with it, and, as we have said, to form a more common
limit of the nature. If the mind attempt this affirmatively from the
first (which it always will when left to itself), there will spring up
phantoms, mere theories and ill-defined notions, with axioms requiring
daily correction. These will, doubtless, be better or worse, according
to the power and strength of the understanding which creates them. But
it is only for God (the bestower and creator of forms), and perhaps
for angels and intelligences, at once to recognize forms affirmatively
at the first glance of contemplation: man, at lest, is unable to do so,
and is only allowed to proceed first by negatives, and then to conclude
with affirmatives, after every species of exclusion.
XVI. We must, therefore, effect a complete solution and separation of
nature; not by fire, but by the mind, that divine fire. The first work
of legitimate induction, in the discovery of forms, is rejection, or
the exclusive instances of individual natures, which are not found in
some one instance where the given nature is present, or are found in
any one instance where it is absent, or are found to increase in any
one instance where the given nature decreases, or the reverse. After an
exclusion correctly effected, an affirmative form will remain as the
residuum, solid, true, and well defined, while all volatile opinions
go off in smoke. This is readily said; but we must arrive at it by a
circuitous route. We shall perhaps, however, omit nothing that can
facilitate our progress.
XVII. The first and almost perpetual precaution and warning which
we consider necessary is this; that none should suppose from the
great part assigned by us to forms, that we mean such forms as the
meditations and thoughts of men have hitherto been accustomed to. In
the first place, we do not at present mean the concrete forms, which
(as we have observed) are in the common course of things compounded
of simple natures, as those of a lion, an eagle, a rose, gold, or the
like. The moment for discussing these will arrive when we come to treat
of the latent process and latent conformation, and the discovery of
them as they exist in what are called substances, or concrete natures.
Nor again, would we be thought to mean (even when treating of simple
natures) any abstract forms or ideas, either undefined or badly defined
in matter. For when we speak of forms, we mean nothing else than those
laws and regulations of simple action which arrange and constitute any
simple nature, such as heat, light, weight, in every species of matter,
and in a susceptible subject. The form of heat or form of light,
therefore, means no more than the law of heat or the law of light.
Nor do we ever abstract or withdraw ourselves from things, and the
operative branch of philosophy. When, therefore, we say (for instance)
in our investigation of the form of heat, Reject rarity, or, Rarity is
not of the form of heat, it is the same as if we were to say, Man can
superinduce heat on a dense body, or the reverse, Man can abstract or
ward off heat from a rare body.
But if our forms appear to any one to be somewhat abstracted, from
their mingling and uniting heterogeneous objects (the heat, for
instance, of the heavenly bodies appears to be very different from that
of fire; the fixed red of the rose and the like, from that which is
apparent in the rainbow, or the radiation of opal or the diamond;[101]
death by drowning, from that by burning, the sword, apoplexy, or
consumption; and yet they all agree in the common natures of heat,
redness, and death), let him be assured that his understanding is
inthralled by habit, by general appearances and hypotheses. For it
is most certain that, however heterogeneous and distinct, they agree
in the form or law which regulates heat, redness, or death; and that
human power cannot be emancipated and freed from the common course
of nature, and expanded and exalted to new efficients and new modes
of operation, except by the revelation and invention of forms of this
nature. But after this[102] union of nature, which is the principal
point, we will afterward, in its proper place, treat of the divisions
and ramifications of nature, whether ordinary or internal and more real.
XVIII. We must now offer an example of the exclusion or rejection
of natures found by the tables of review, not to be of the form of
heat; first premising that not only each table is sufficient for the
rejection of any nature, but even each single instance contained in
them. For it is clear from what has been said that every contradictory
instance destroys a hypothesis as to the form. Still, however, for the
sake of clearness, and in order to show more plainly the use of the
tables, we redouble or repeat the exclusive.
_An Example of the Exclusive Table, or of the Rejection of Natures
from the Form of Heat_
1. On account of the sun’s rays, reject elementary (or terrestrial)
nature.
2. On account of common fire, and particularly subterranean fires
(which are the most remote and secluded from the rays of the heavenly
bodies), reject celestial nature.
3. On account of the heat acquired by every description of substances
(as minerals, vegetables, the external parts of animals, water, oil,
air, etc.) by mere approximation to the fire or any warm body, reject
all variety and delicate texture of bodies.
4. On account of iron and ignited metals, which warm other bodies, and
yet neither lose their weight nor substance, reject the imparting or
mixing of the substance of the heating body.
5. On account of boiling water and air, and also those metals and other
solid bodies which are heated, but not to ignition, or red heat, reject
flame or light.
6. On account of the rays of the moon and other heavenly bodies (except
the sun), again reject flame or light.
7. On account of the comparison between red-hot iron and the flame of
spirits of wine (for the iron is more hot and less bright, while the
flame of spirits of wine is more bright and less hot), again reject
flame and light.
8. On account of gold and other ignited metals, which are of the
greatest specific density, reject rarity.
9. On account of air, which is generally found to be cold and yet
continues rare, reject rarity.
10. On account of ignited iron,[103] which does not swell in bulk, but
retains the same apparent dimension, reject the absolute expansive
motion of the whole.
11. On account of the expansion of the air in thermometers and the
like, which is absolutely moved and expanded to the eye, and yet
acquires no manifest increase of heat, again reject absolute or
expansive motion of the whole.
12. On account of the ready application of heat to all substances
without any destruction or remarkable alteration of them, reject
destructive nature or the violent communication of any new nature.
13. On account of the agreement and conformity of the effects produced
by cold and heat, reject both expansive and contracting motion as
regards the whole.
14. On account of the heat excited by friction, reject principal
nature, by which we mean that which exists positively, and is not
caused by a preceding nature.
There are other natures to be rejected; but we are merely offering
examples, and not perfect tables.
None of the above natures are of the form of heat; and man is freed
from them all in his operation upon heat.
XIX. In the exclusive table are laid the foundations of true induction,
which is not, however, completed until the affirmative be attained. Nor
is the exclusive table perfect, nor can it be so at first. For it is
clearly a rejection of simple natures; but if we have not as yet good
and just notions of simple natures, how can the exclusive table be made
correct? Some of the above, as the notion of elementary and celestial
nature, and rarity, are vague and ill defined. We, therefore, who are
neither ignorant nor forgetful of the great work which we attempt, in
rendering the human understanding adequate to things and nature, by
no means rest satisfied with what we have hitherto enforced, but push
the matter further, and contrive and prepare more powerful aid for the
use of the understanding, which we will next subjoin. And, indeed, in
the interpretation of nature the mind is to be so prepared and formed,
as to rest itself on proper degrees of certainty, and yet to remember
(especially at first) that what is present depends much upon what
remains behind.
XX. Since, however, truth emerges more readily from error than
confusion, we consider it useful to leave the understanding at liberty
to exert itself and attempt the interpretation of nature in the
affirmative, after having constructed and weighed the three tables of
preparation, such as we have laid them down, both from the instances
there collected, and others occurring elsewhere. Which attempt we are
wont to call the liberty of the understanding, or the commencement of
interpretation, or the first vintage.
_The First Vintage of the Form of Heat_
It must be observed that the form of anything is inherent (as appears
clearly from our premises) in each individual instance in which the
thing itself is inherent, or it would not be a form. No contradictory
instance, therefore, can be alleged. The form, however, is found
to be much more conspicuous and evident in some instances than in
others; in those (for example) where its nature is less restrained
and embarrassed, and reduced to rule by other natures. Such instances
we are wont to term coruscations, or conspicuous instances. We must
proceed, then, to the first vintage of the form of heat.