and perverse methods, ill adapted to the nature of the body upon which he operates. A clear path, therefore, towards this object, also must be thrown open, and well supported.

Labour is well and usefully bestowed upon the anatomy of organized bodies, such as those of men and animals, which appears to be a subtile matter, and a useful examination of nature. This species of anatomy, however, is that of first sight, open to the senses, and takes place only in organized bodies. It is obvious, and of ready access, when compared with the real anatomy of latent conformation in bodies which are considered similar, particularly in specific objects and their parts: as those of iron, stone, and the similar parts of plants and animals, as the root, the leaf, the flower, the flesh, the blood, and bones, &c. Yet human industry has not completely neglected this species of anatomy: for we have an instance of it in the separation of similar bodies by distillation, and other solutions, which shows the dissimilarity of the compound, by the union of the homogeneous parts. These methods are useful, and of importance to our inquiry, although attended generally with fallacy for many natures are assigned and attributed to the separate bodies, as if they had previously existed in the compound, which, in reality, are recently bestowed and superinduced by fire and heat, and the other modes of separation. Besides, it is, after all, but a small part of the labour of discovering the real conformation in the compound, which is so subtile and nice, that it is rather confused and lost by the operation of the fire, than discovered and brought to light.

A separation and solution of bodies, therefore, is to be effected, not by fire indeed, but rather by reasoning and true induction, with the assistance of experiment, and by a comparison with other bodies, and a reduction to those simple natures and their forms, which meet and are combined in the compound; and we must assuredly pass from Vulcan to Minerva, if we wish to bring to light the real texture and conformation of bodies, upon which every occult and (as it is sometimes called) specific property and virtue of things depends, and whence, also, every rule of powerful change and transformation is deduced.

For instance, we must examine what spirit is in every body, what tangible essence; whether that spirit is copious and exuberant, or meagre and scarce, fine or coarse, aeriform or igniform, active or sluggish, weak or robust, progressive or retrograde, abrupt or continuous, agreeing with external and surrounding objects, or differing from them, &c. In like manner must we treat tangible essence, (which admits of as many distinctions as the spirit,) and its hairs, fibres, and varied texture. Again, the situation of the spirit in the corporeal mass, its pores, passages, veins, and cells, and the rudiments or first essays of the

organic body are subject to the same examination. In these, however, as in our former inquiries, and therefore in the whole investigation of latent conformation, the only genuine and clear light which completely dispels all darkness and subtile difficulties, is admitted by means of the primary axioms.

8. This method will not bring us to atoms,* which takes for granted the vacuum, and the immutability of matter, (neither of which hypotheses is correct;) but to the real particles, such as we discover them to be. Nor is there any ground for alarm at this refinement, as if it were inexplicable, for, on the contrary, the more inquiry is directed to simple natures, the more will every thing be placed in a plain and perspicuous light; since we transfer our attention from the complicated to the simple, from the incommensurable to the commensurable, from surds to rational quantities, from the indefinite and vague to the definite and certain: as when we arrive at the elements of letters, and the simple tones of concords. The investigation of nature is best conducted when mathematics are applied to physics. Again, let none be alarmed at vast numbers and fractions; for, in calculation, it is as easy to set down or to reflect upon a thousand as a unit, or the thousandth part of an integer as an integer itself.

9. From the two kinds of axioms above specified arise the two divisions of philosophy and the sciences, and we will use the commonly adopted terms, which approach the nearest to our meaning, in our own sense. Let the investigation of forms, which (in reasoning at least, and after their own laws) are eternal and immutable, constitute metaphysics, and let the investigation of the efficient cause of matter, latent process, and latent conformation (which all relate merely to the ordinary course of nature, and not to her fundamental and eternal laws) constitute physics. Parallel to these let there be two practical divisions; to physics that of mechanics, and to metaphysics that of magic, in the purest sense of the term, as applied to its ample means and its command over nature.

10. The object of our philosophy being thus laid down, we proceed to precepts, in the most clear and regular order. The signs for the interpretation of nature comprehend two divisions: the first regards the eliciting or creating of axioms from experiment, the second the deducing or deriving of new experiments from axioms. The first admits of three subdivisions into ministrations. 1. To the senses. 2. To the memory.

rum

But natural and experimental history is so varied and diffuse, that it confounds and distracts the understanding unless it be fixed and exhibited in due order. We must, therefore, form tables and co-ordinations of instances, upon such a plan, and in such order, that the understanding may be enabled to act upon them.

Even when this is done, the understanding, left to itself and its own operation, is incompetent and unfit to construct its axioms without direction and support. Our third ministration, therefore, must be true and legitimate induction, the very key of interpretation. We must begin, however, at the end, and go back again to the others.

11. The investigation of Forms proceeds thus: A nature being given, we must first present to the understanding all the known instances which agree in the same nature, although the subject-matter be considerably diversified. And this collection must be made as a mere history, and without any premature reflection, or too great degree of refinement. For instance: take the investigation of the form of heat.

17. Green and moist vegetable matter confined and rubbed together; as roses, peas in baskets; so hay, if it be damp when stacked, often catches fire.

18. Quicklime sprinkled with water.

19. Iron, when first dissolved by acids in a glass, and without any application to fire; the same of tin, but not so intensely.

20. Animals, particularly internally; although the heat is not perceivable by the touch in insects, on account of their small size.

21. Horse dung, and the like excrement from other animals, when fresh.

22. Strong oil of sulphur and of vitriol exhibit the operation of heat in burning linen.

23. As does the oil of marjoram, and like substances, in burning the bony substance of the teeth.

24. Strong and well rectified spirits of wine exhibit the same effects; so that white of eggs when thrown into it, grows hard and white, almost in the same manner as when boiled, and bread becomes burnt and brown as if toasted.

25. Aromatic substances and warm plants, as the dracunculus [arum,] old nasturtium, &c.; which, though they be not warm to the touch, (whether whole or pulverized,) yet are discovered by the tongue and palate to be warm and almost burning when slightly masticated.

26. Strong vinegar and all acids, or any part of the body not clothed with the epidermis, as the eye, tongue, or any wounded part, or where the skin is removed, excite a pain differing but little from that produced by heat.

27. Even a severe and intense cold produces a sensation of burning.*

"Nam Boreæ penetrabile frigus adurit." 28. Other instances.

We are wont to call this a table of existence and presence.

12. We must next present to the understanding instances which do not admit of the given nature; for form (as we have observed) ought no less to be absent where the given nature is absent, than to be present where it is present. If, however, would be infinite. we were to examine every instance, our labour

Negatives, therefore, must be classed under the affirmatives, and the want of the given nature must be inquired into more particularly in objects which have a very close connexion with those others in which it is present and manifest. And this we are wont to term a table of deviation o of absence in proximity.

"Ne tenues pluviæ, rapidive potentia solis
Acrior, aut Bores penetrabile frigus adurat."
Virg. Georg. I. v. 92, 93.

The rays of the moon, stars, and comets, are not found to be warm to the touch, nay, the severest cold has been observed to take place at the full of the moon. Yet the larger fixed stars are supposed to increase and render more intense the heat of the sun, as he approaches them; when the sun is in the sign of the lion, for instance, and in the dog-days.

Second negative to the second affirmative.

The rays of the sun in what is called the middle region of the air give no heat, to account for which the commonly assigned reason is satisfactory; namely, that that region is neither sufficiently near to the body of the sun, whence the rays emanate, nor to the earth, whence they are reflected. And the fact is manifested by snow being perpetual on the tops of mountains, unless extremely lofty. But it is observed on the other hand by some, that at the Peak of Teneriffe, and also among the Andes of Peru, the tops of the mountains are free from snow, which only lies in the lower part, as you ascend. Besides, the air on the summit of these mountains is found to be by no means cold, but only thin and sharp; so much so, that in the Andes, it pricks and hurts the eyes from its extreme sharpness, and even excites the orifice of the stomach and produces vomiting. The ancients also observed, that the rarity of the air on the summit of Olympus, was such, that those who ascended it, were obliged to carry sponges moistened with vinegar and water, and to apply them now and then to their nostrils, as the air was not dense enough for their respiration; on the summit of which mountain it is also related, there reigned so great a serenity and calm, free from rain, snow, or wind, that the letters traced upon the ashes of the sacrifices on the altar of Jupiter, by the fingers of those who had offered them, would remain undisturbed till the next year. Those even, who, at this day, go to the top of the Peak of Teneriffe, walk by night and not in the daytime, and are advised and pressed by their guides, as soon as the sun rises, to make haste in their descent, on account of the danger, (apparently arising from the rarity of the atmosphere,) lest their breathing should be relaxed and suffocated.

Third negative to the second affirmative. The reflection of the solar rays in the polar gions is found to be weak and inefficient in producing heat; so that the Dutch, who wintered in Nova Zembla, and expected that their vessels would be freed about the beginning of July from the obstruction of the mass of ice which had blocked it up, were disappointed and obliged to embark in their boat. Hence the direct rays

on the plain, and when reflected, unless they are multiplied and condensed, which takes place when the sun tends more to the perpendicular; for then the incidence of the rays occurs at more acute angles, so that the reflected rays are nearer to each other, whilst, on the contrary, when the sun is in a very oblique position, the angles of incidence are very obtuse and the reflected rays at a greater distance. In the mean time it must be observed, that there may be many operations of the solar rays, relating too to the nature of heat, which are not proportioned to our touch, so that, with regard to us, they do not tend to produce warmth, but, with regard to some other bodies, have their due effect in producing it.

Take

Fourth negative to the second affirmative. Let the following experiment be made. a lens the reverse of a burning glass, and place it between the hand and the solar rays, and observe whether it diminish the heat of the sun, as a burning glass increases it. For it is clear, with regard to the visual rays, that, in proportion as the lens is made of unequal thickness in the middle and at its sides, the images appear either more diffused or contracted. It should be seen, therefore, if the same be true with regard to heat.

Fifth negative to the second affirmative. Let the experiment be well tried, whether the lunar rays can be received and collected by the strongest and best burning-glasses, so as to produce even the least degree of heat. But if that degree be, perhaps, so subtile and weak, as not to be perceived or ascertained by the touch, we must have recourse to those glasses which indicate the warm or cold state of the atmosphere, and let the lunar rays fall through the burning glass on the top of this thermometer, and then notice if the water be depressed by the heat.*

Sixth negative to the second affirmative. Let the burning-glass be tried on warm objects which emit no luminous rays, as heated, but not ignited iron or stone, or hot water, or the like; and observe whether the heat become increased and condensed, as happens with the solar rays. Seventh negative to the second affirmative. Let it be tried on common flame.

Eighth negative to the third affirmative. The effect of comets, (if we can reckon them amongst meteors,) in augmenting the heat of the season, is not found to be constant or clear, although droughts have generally been observed to follow them. However, luminous lines, and pil

in the table of the degrees of heat. It serves also as a barometer, but is inaccurate in both capacities.

*For the construction of Bacon's thermometer see No. 38

lars, and openings, and the like, appear more often in winter than in summer, and especially with the most intense cold, but joined with drought. Lightning, and coruscations, and thunder, however, rarely happen in winter, and generally at the time of the greatest heats. The appearances we term falling stars, are generally supposed to consist of some shining and enflamed viscous substance, rather than of violently hot matter. But let this be further investigated.

Ninth negative to the fourth affirmative. Some coruscations emit light without burning; but are never accompanied by thunder.

Tenth negative to the fifth affirmative. Eructations and eruptions of flame are to be found in cold climates as well as in hot, as in Iceland and Greenland; just as the trees of cold countries are sometimes inflammable, and more pitchy and resinous than in warm; as the fir, pine, and the like. But the position and nature of the soil, where such eruptions are wont to happen, is not yet sufficiently investigated to enable us to subjoin a negative instance to the affirmative.

Eleventh negative to the sixth affirmative.

*

All flame is constantly more or less warm, and this instance is not altogether negative. Yet, it is said, that the ignis fatuus, (as it is called,) and which sometimes is driven against walls, has but little heat; perhaps it resembles that of spirits of wine, which is mild and gentle. That flame, however, appears yet milder, which, in some well authenticated and serious histories, is said to have appeared round the head and hair of boys and virgins, and instead of burning their hair, merely to have played about it. And it is most certain that a sort of flash, without any evident heat, has sometimes been seen about a horse when sweating at night, or in damp weather. It is also a well known fact, and it was almost considered as a miracle, that, a few years since, a girl's apron sparkled when a little shaken or rubbed; which was, perhaps, occasioned by the alum or salts with which the apron was imbued, and which, after having been stuck together and incrusted rather strongly, were broken by the friction. It is well known that all sugar, whether candied or plain, if it be hard, will sparkle when broken or scraped in the dark. In like manner sea and salt water is sometimes found to shine at night when struck violently by the oar. The foam of the sea, when agitated by tempests, also sparkles at night, and the Spaniards call this appearance the sea's lungs. It has not been sufficiently ascertained what degree of heat attends the flame which the ancient sailors called Castor and Pollux, and the moderns call St. Ermus's fire.

* Was it a silk apron, which will exhibit electric sparks? but silk was then scarce.

VOL. III.-48

Twelfth negative to the seventh affirmative. Every ignited body that is red-hot is always warm, although without flame, nor is any negative instance subjoined to this affirmative. Rotten wood, however, approaches nearly to it, for it shines at night, and yet is not found to be warm; and the putrefying scales of fish, which shine in the same manner, are not warm to the touch, nor the body of the glow-worm, or of the fly called lucciola.*

Thirteenth negative to the eighth affirmative.

The situation and nature of the soil of natural warm baths has not been sufficiently investigated, and, therefore, a negative instance is not subjoined.

Fourteenth negative to the ninth affirmative.

To the instances of warm liquids we may subjoin the negative one of the peculiar nature of liquids in general. For no tangible liquid is known that is at once warm in its nature and constantly continues warm; but their heat is only superinduced as an adventitious nature for a limited time; so that those which are extremely warm in their power and effect, as spirits of wine, chymical aromatic oils, the oils of vitriol and sulphur, and the like, and which speedily burn, are yet cold at first to the touch, and the water of natural baths, poured into any vessel and separated from its source, cools down like water heated by the fire. It is, however, true, that oily substances are rather less cold to the touch than those that are aqueous, oil for instance than water, silk than linen; but this belongs to the table of degrees of cold.

Fifteenth negative to the tenth affirmative.

In like manner we may subjoin a negative instance to that of warm vapour, derived from the nature of vapour itself; as far as we are acquainted with it. For exhalations from oily substances, though easily inflammable, are yet never warm unless recently inhaled from some warm substance.

Sixteenth negative to the tenth affirmative.

The same may be said of the instance of air. For we never perceive that air is warm, unless confined or pressed, or manifestly heated by the sun, by fire, or some other warm body.

Seventeenth negative to the eleventh affirmative. A negative instance is exhibited in weather by its coldness with an east or north wind, beyond what the season would lead us to expect; just as the contrary takes place with the south or west winds. An inclination to rain (especially in winter) attends warm weather, and to frost cold weather.

Eighteenth negative to the twelfth affirmative.

A negative instance as to air confined in caverns

may be observed in summer. Indeed we should make a more diligent inquiry into the nature of confined air. For, in the first place, the qualities of air in its own nature with regard to heat and cold, may reasonably be the subject of doubt. For air evidently derives its heat from the effects of celestial bodies, and possibly its cold from the exhalation of the earth, and in the mid region of air (as it is termed) from cold vapours and snow, so that no judgment can be formed of the nature of air by that which is out of doors and exposed, but a more correct one might be derived from confined air. It is necessary, however, that the air should be enclosed in a vessel of such materials as would not imbue it with heat or cold of themselves, nor easily admit the influence of the exterternal atmosphere. The experiment should be made therefore with an earthen jar, covered with folds of leather to protect it from the external air, and the air should be kept three or four days in this vessel well closed. On opening the jar, the degree of heat may be ascertained either by the hand or a graduated glass tube.

Nineteenth negative to the thirteenth affirmative.

There is a similar doubt as to whether the warmth of wool, skins, feathers, and the like, is derived from a slight inherent heat, since they are animal excretions, or from their being of a certain fat and oily nature that accords with heat, or merely from the confinement and separation of air which we spoke of in the preceding paragraph.* For all air appears to possess a certain degree of warmth when separated from the external atmosphere. Let an experiment be made, therefore, with fibrous substances of linen, and not of wool, feathers, or silk, which are animal excretions. For it is to be observed that all powders (where air is manifestly enclosed) are less cold than the substances when whole, just as we imagine froth (which contains air) to be less cold han the liquid itself.

Twentieth negative to the fourteenth affirmative. We have here no exactly negative instance, for we are not acquainted with any body tangible or spirituous which does not admit of heat when exposed to the fire. There is, however, this difference, that some admit it more rapidly, as air, oil, and water, others more slowly, as stone and metals. This, however, belongs to the table of degrees.

mark that sparks are not kindled by flint and steel, or any other hard substance, unless some small particles of the stone or metal are struck off, and that the air never forms them by friction, as is commonly supposed; besides, the sparks from the weight of the ignited substance, have a tendency to descend rather than to rise, and when extinguished become a sort of dark ash.

Twenty-second negative to the sixteenth affirmative. We are of opinion that here again there is no negative. For we are not acquainted with any tangible body which does not become decidedly warm by friction, so that the ancients feigned that the gods had no other means or power of creating heat than the friction of air, by rapid and violent rotation. On this point, however, further inquiry must be made, whether bodies projected by machines (as balls from cannon) do not derive some degree of heat from meeting the air, which renders them somewhat warm when they fall. The air in motion rather cools than heats, as in the winds, the bellows, or breath when the month is contracted. The motion, however, in such instances is not sufficiently rapid to excite heat, and is applied to a body of air and not to its component parts, so that it is not surprising that heat should not be generated.

Twenty-third negative to the seventeenth affirmative. We must make a more diligent inquiry into this instance. For herbs, and green and moist vegetables appear to possess a latent heat, so small, however, as not to be perceived by the touch in single specimens, but when they are united and confined, so that their spirit cannot exhale into the air, and they rather warm each other, their heat is at once manifested, and even flame occasionally in suitable substances.

Twenty-fourth negative to the eighteenth affirmative.

Here, too, we must make a more diligent inquiry. For quicklime, when sprinkled with water, appears to conceive heat, either from its being collected into one point, (as we observed of herbs when confined,) or from the irritation and exasperation of the fiery spirit by water, which occasions a conflict and struggle. The true reason will more readily be shown if oil be used instead of water, for oil will equally tend to collect the confined spirit, but not to irritate. The experiment may be made more general, both by using the ashes and calcined products of different bodies, and by pouring different liquids upon them.

Twenty-fifth negative to the nineteenth affirmative. A negative instance may be subjoined of other metals which are more soft and soluble. For leaf gold dissolved by aqua regia, or lead by aqua fortis, are not warm to the touch whilst dissolving, no more is quicksilver, (as far as I remember,) but