« ZurückWeiter »
others: of which fluid when our bodies are totally deprived, they are said to be frozen; when they have a proper quantity, they are in health, and fit to perform all their functions; it is then called natural heat: when too much, it is called fever; and when forced into the body in too great a quantity from without, it gives pain by separating and des troying the flesh, and is then called burning; and the fluid so entering and acting is called fire.
While organized bodies, animal or vegetable, are augmenting in growth, or are supplying their continual waste, is not this done by attracting and consolidating this fluid called fire, so as to form of it a part of their substance? and it is not a separation of the parts of such substance, which, dissolving its solid state, sets that subtle fluid at liberty, when it again makes its appearance as fire?
For the power of a man relative to matter seems limited to the dividing it, or mixing the various kinds of it, or changing its form and appearance by differing compositions of it; but does not extend to the making or creating of new matter, or annihilating the old: thus, if fire be an original element, or kind of matter, its quantity is fixed and permanent in the world. We cannot destroy any part of it, or make addition to it; we can only separate it from that which confines it, and so set it at liberty, as when we put wood in a situation to be burnt; or transfer it from one solid to another, as when we make lime by burning stone, a part of the fire dislodged from the wood being left in the stone. May not this fluid, when at liberty, be capable of penetrating and entering into all bodies, organized or not; quitting easily in totally those not organized; and quitting easily in part those which are; the part assumed and fixed remaining till the body is dissolved?
Is it not this fluid which keeps asunder the particles of air, permitting them to approach, or separating them more, in proportion as its quantity is diminished or augmented? Is it not the greater gravity of the particles of air, which forces the particles of
this fluid to mount with the matters to which it is attached, as smoke or vapour?
Does it not seem to have a great effinity with water, since it will quit a solid to unite with that fluid, and go off with it in vapour, leaving the solid cold to the touch, and the degree measurable by the thermometer?
The vapour rises attached to this fluid; but at a certain height they separate, and the vapour descends in rain, retaining but little of it, in snow or hail less. What becomes of that fluid? Does it rise above our atmosphere, and mix equally with the universal mass of the same kind? Or does a spherical stratum of it, denser, or less mixed with air, attracted by this globe, and repelled or pushed up only to a certain height from its surface, by the greater weight of air remain there surrounding the globe, and proceeding with it round the sun?
In such case, as there may be a continuity or communication of this fluid through the air quite down to the earth, is it not by the vibrations given to it by the sun that light appears to us; and may it not be, that every one of the infinitely small vibrations, striking common matter with a certain force,enter its substance, are held there by attraction, and augmented by succeeding vibrations, till the matter has received as much as their force can drive into it?
Is it not thus that the surface of this globe is continually heated by such repeated vibrations in the day, and cooled by the escape of that heat when those vibrations are discontinued in the night, or intercepted and reflected by clouds?
Is it not thus that fire is amassed, and makes the greatest part of the substance of combustible bodies? Perhaps when this globe was first formed, and its original particles took their place at certain distances from the centre, in proportion to their greater or less gravity, the fluid fire, attracted towards that centre, might in great part be obliged, as lightest, to take place above the rest, and thus form the sphere of fire above supposed, which would afterwards be continually diminishing by the substance it afforded to organ.
ized bodies; and the quantity restored to it again by the burning or other separating of the parts of those bodies.
Is not the natural heat of animals thus produced by separating in digestion the parts of food, and set ting their fire at liberty?
Is it not this sphere of fire which kindles the wan dering globes that sometimes pass through it in our course round the sun, have their surface kindled by it, and burst when their included air is greatly rarified by the heat on the burning surfaces?
fore imagined that the internal parts might be a fluid more dense, and of greater specific gravity than any of the solids we are acquainted with; which therefore might swim in or upon that fluid. Thus the surface of the globe would be a shell, capable of being broken and disordered by the violent movements of fluid on which it rested. And, as air has been compressed by art so as to be twice as dense as water, in which case, if such air and water could be contained in a strong glass vessel, the air would be seen to take the lowest place, and the water to floa above and upon it; and, as we know not yet the degree of density to which air may be compressed, and M. Amontons calculated, that, its density increasing as it approached the centre in the same proportion as above the surface, it would at the depth of leagues, be heavier than gold, possibly the dense fluid occupying the internal parts of the globe might be air compressed. And as the force of expansion in dense air when heated, is in proportion to its density; this central air might afford another agent to move the surface, as well as be of use in keeping alive the central fires; though, as you observe, the sudden rarefaction of water, coming into contact with those fires, may be an agent sufficiently strong for that purpose, when acting between the incumbent and the fluid on which it rests.
If one might indulge imagination in supposing how such a globe was formed, I should conceive, that all the elements in separate particles, being originally mixed in confusion, and occupying a great space, they would as soon (as soon as the Almighty Gat ordained gravity, or the mutual attraction of certain parts, and the mutual repulsion of other parts, to exist) all move towards their common centre: that the air being a fluid whose parts repel each other, though drawn to the common centre by their gravity, would be densest towards the centre, and rarer as more remote; consequently, all bodies, lighter than the central parts of that air, and immersed in it, would recede from the centre, and rise till they arrive at that region of the air, which was of the saine specific gravity with themselves, where they would rest; while