By these experiments we have a clear idea of the means and method by which fermentation is performed, which operation has been hitherto unintelligible. From hence we may likewise see the reason why, in an air either too hot or too cold, fermentation cannot be performed; for in an air too cold, the pressure is too great, and also the grains of air too large to enter and divide the thing to be fermented; by which means the motion of its parts requisite to fermentation is prevented; but in air that is too hot, there must be just the contrary effect, for there the parts of the thing to be fermented are so far expanded, and the air so rarified, as to pass through the body with little or no obstruction, and of consequence to produce little or no intestine motion of its parts; and that there is in fermentations an intestine motion of the parts of a fermenting liquid, is easily discernible by the naked eye. This also gives us the reason, why the glow-worm shines only in the summer months, when the air is greatly rarified, or divided, and then requires but a small motion to give it the form of light.
The light proceeding from diamonds &c. seems to be easily accounted for from the motion of the airs; that there is a perpetual motion of the airs, may be proved by the following experiment. In a still place, suppose a close darkened room, illuminated only by one small hole in the window shutter; where, if a person at rest views the enlightened current of air sideways, as it extends along the room, he will perceive a surprising motion of the dusty atoms therein, perpetually rolling and tossing about with great rapidity. This motion must be very considerable, as it is perpetual, and pushed on with the power of gravity in the air equal to a column of water 33 feet high. By this action on diamonds, whose pores are very small, and the bodies themselves of such a make and hardness, as that, when the air is pressed on them with so great a force as that of the incumbent atmosphere, the air is broke exceedingly small, and, by the continuance of the pressure, is sent off from the body in form of light. We likewise find from experiments, that where diamonds, or other bodies of that kind, have not their outward parts of a proper make, or their substance of a sufficient hardness or closeness of parts, to emit light with no greater force, than the pressure of the atmosphere only, then this deficiency may be supplied by rubbing; by which means the air is ground to pieces, and emitted in form of light, as is shewn in all electrical experiments.
One great property of light, or, as it is commonly called the electrical effluvia, is (as Mr. Hauksbee has proved from many experiments,) that it passes through glass, as water does through a sieve, or as if no body of matter interposed. This light of itself, when pure, or simple, hurts or destroys no material bodies; but when pushed on by the following air with great violence, and meeting with a great resistance from an impeding body, the conflict is so great, that if the following air presses on with sufficient violence, it dissolves or destroys the solidity of any material body. As all bodies become solid according to the temperature of the surrounding air; some retaining their solidity in such a degree of heat, as metals of most kinds; whilst others require a particular degree of cold before they become solid, as water &c. which when froze is as much a solid as any thing else—this proves that the solidity of bodies depends on the temperature of the air, as will be more fully proved hereafter.
The glass globe, with the electrical experiments, seems to give a very clear idea in what manner the sun is supported, how this terraqueous globe and the rest of the planets are made to move, and continued in motion; and also, what is the cause of the attraction of the sun, earth, moon and the rest of the planets.
That the sun is the chief, material, ruling agent, is very clearly revealed; as are some of its chiefest actions on the planets and the rest of the universe. For, in the sun we find a power of melting, dividing and (with the assistance of the air) expanding and sending out the air, first in form of fire, and afterwards in that of light; which power seems to be so regulated, as to be able to reach the extremities of the universe, where it is congealed, condensed, and returned back again to the sun, to be again melted, divided, and sent out as before. This action seems to be represented by water in a still, for there the fire, forcing its way through the water contained in the still, carries off some of the watry particles with it; and when it has reached the head of the still, if it has no passage into the outward air, and the action of the fire is not great enough to break the still, it is by the coldness of the surrounding air (or as is commonly the case by the coldness of water placed thereon for that purpose) condensed and returned into the water contained in the body of the still, there to be rarified, expanded, and sent off in steam, as before.
We must suppose the streams of light to be always acting on one side of this terraqueous globe, and there dividing, expanding and rarifying the air; the consequence of which must be a kind of vacuum, which is immediately filled by the pressing in of the congealed air from the extremities; and as the earth is placed in this fluid of airs, we may as easily conceive that the air pressing in as above, must, with it, turn round the earth, in the same manner, and with as much ease, as water does a common mill-wheel, or the air a wind-mill. By these powers also the terraqueous globe is kept solid and entire; for, was this force once taken off, it would soon drop to atoms, notwithstanding the pretended attracting power of its materials.
To confirm what is here advanced, I shall bring an experiment (which Mr. Boyle has laid down as a paradox) which proves that this terraqueous globe has no attraction, nor any solid, falling towards it, any gravitation; but that all bodies are forced to it by the incumbent atmosphere, as much as water is forced up a pump by it (the atmosphere) which, till the time of the great Mr. Boyle, was imagined to be performed by, what they called, the suction of the pump. But this is no more than has often happened in philosophy, where when we cannot well account for any thing, we put the effect for the cause.
Mr. Boyle found that a solid body, as ponderous as any yet known, though near the top of the water it would sink by its own weight, yet if it be placed at a greater depth than twenty times its own thickness, it will not sink, if its descent be not assisted by the weight of the incumbent water. To prove this, he gives us a curious experiment, viz. by keeping off the pressure of the water, from the top of the sinking body, and sinking it to a proper depth, he found, that the most ponderous body would be buoyed up, and supported by the water only. See the 2d vol. of Boulton’s epitome, pag. 305. This experiment shews us beyond all contradiction, that the earth has no power of attraction, nor a descending body any power of gravitation; for if it had, the farther it was sunk in the water, the nearer it must be to the centre of the earth, and of consequence the attraction must be the greater; but this, we find, is contrary to experience; so that the whole power of descending is impressed upon it by the air, or by other bodies forced upon it by the incumbent air. This experiment alone is more than sufficient to destroy the fine theories of attraction and gravitation; it also shews us how, and by what means, two marble slabs, finely polished, are what they call attracted to each other, and require a great force to separate them; a force in proportion to the breadth of the slabs; but this has been shewn by other experiments to be nothing but the pressure of the air, or atmosphere; for put them into an air pump, and extract the gross air, and they will immediately separate from each other.