that all are divided, or balanced to near the fame Gravity of the Fluids, fome few Parts of the earthy or crafs Matter will leifurely fubfide, and fome few of the lighter will swim, and the reft be quiet; as old Ale, Wine, &c. till put into a new ferment by Motion, or fome other Accident or Agent. Where the Corpufcles that constitute the Fluid are of near the fame Gravity, fuch as diftilled Spirits, &c. they cannot be put into fermentation by any Motion, nor will they diffolve any Body immersed in them. But the Matter in the Stomach is of various Gravities always compreft by the Air without, and extended by Steam within, because it requires a great force to drive the Steam along the Fluids in the Blood-veffels, quite out at the Lungs and Pores. And whilft the Lungs play, the Stomach and Guts are never fuffered to lie one Minute ftill, fo nothing in it can cease to ferment and emit the Steam, unless there be fuch a Quantity of Matter fo cold, or fo incapable of being acted upon, that the Agents be overpowered.

These volatile and active Salts and Corpufcles of Fire act much the fame Part, and after the fame manner, upon Matter in the Fluids within the Stomach, as Fire

or

or active Salts do upon Fuel in the Fluid of Air in a furnace. The Preffure of the Air and of the Fluid, and the Motion of the Fluid moves, and enforces the Corpuf cles of volatile and active Salts and Fire, to act upon and divide the Bodies in the Fluid, as the Preffure and Motion of the Air moves and enforces the Corpufcles of Fire and active Salts, to act upon and divide the Parts of the Fuel in the Air. And Fluids beat back the Corpufcles of Salt to the Matter, as the Air does those of Fire to the Fluel. And 'tis likely that the Corpufcles of volatile Salt, bear near the fame Proportion of Gravity to Water, as those of Fire do to Air, and as there are Fluids of different Gravities, fo there are Salts of like different Gravities, and 'tis likely of different Sizes, to fit the Pores of different Bodies, and 'tis likely the lightest fort, which I call active, and fome of the volatile Salts, act jointly with Fire upon Fuel in the Air, as 'tis vifible they do in Sulphur, as well as those of Fire act with Salts in the Fluid of Water, &c. And fome active Salts or Spirits, when very pure, raise a Steam, wh n exposed to the Air, nearly resembling Flame or the Corpufcles of fire, pure and nearly united. And the Diffolution of Bodies VOL. X.

C

by

by volatile Salts, &c. frees more Corpuf cles of volatile Salts, &c. as the Diffolu tion of Bodies by fire frees more Corpuf cles of Fire; and thereby the Actions are encreased; if the Motion continue, and there be fufficient fit Matter to work upon in Proportion to the Agents, freed Salts by their Agitation, and the Rebounds of them, and the Parts they divide, expand the Fluid containing them, in Proportion to their Motion and Agitation, as thofe of Fire do that of Air. Salts, and Fire, and Air, bear off the fmall Particles which adhere to them in form of steam from the Stomach, as fire does fmall Parts of the Fuel, in form of Sparks or Smoke, and that Matter which is too heavy to be born off, and which the Strength of the Agents is not fufficient to divide,. fubfide as Cinders, Afhes, &c. do in Fire in the Fluid of Air. contains Corpufcles of Fire, as Water does thofe of Salts diffufedly, and when fuch a Quantity of fire or Salt is collected as to act, those of the fame fort join, fix upon the Body, and affift, as the Air or fluid moves them thither. Corpuscles of fire or Heat, as is moft vifible in Rooms where there is Fire burning and People perfpiring them, are agitated, divide the Bodies in the Air, and perhaps the united

Air

Cor

Corpufcles of Air, and expand or adhere to the Corpufcles of Air, &c. and make them lighter, fo that the Preffure of the circumjacent Air bears them up the Chimney, and fresh Air fucceeds them, to agitate the Fire, and make its Corpuf cles move and act; and 'tis likely supply more Corpufcles of fire, and perhaps with fome nitrous or other Matter like Cold, because it burns better in cold Weather than in hot. In like manner the light Matter in fluids rifes, and the fucceeding Fluid fupplies more Salts, &c. Thus ripe fern-feed, when one has ftript them out of their Codds, and by the Preffure of the Air, or by the Corpufcles of Heat in it, their Skins burst, by that force and their own Elasticity jump up, fall down, and rebound so as to make a mighty Buftle. Thus the Corpufcles of fome small fharp Salts called Acids, in a Fluid preffed by the Air, inftantly enter the Pores, fplit, and divide the Particles of fome other Salts, and jet the Parts each Way, and they rebound from one another, or are preffed back by the Air fo as to cause a mighty Buftle and Explofion, and raise a fume like Smoke, and a small Quantity of them in the Stomach by the fame Operation caufe a fudden Effervefcence there, and fweat all over the Body. Thus C 2

the

the Corpufcles of fire, moved quickly by the Preffure of the Air into the powdered Charcoal and Sulphur, and exciting the latent Corpufcles of fire and volatile Salts in them mixed among the Particles of Nitre, fuddenly fplit them, and expand and burft the fmall Maffes, and the split Parts by that Preffure, their own Elafticity, the Elafticity of the Air, and the Rebounds from any Thing which resists their Expanfion, caufe that terrible Explofion, and drives them off in form of Steam or Smoke, with that infinite force and Velocity, which we fee in fired Gunpowder, that Way where it gets Vent; and in Proportion to the Space it has for Vent, and of the Sides which refift and encrease its force by rebounding. As the force of fire is encreased by being confined and rebounded on more Sides, more, fo there be but fufficient Room to admit the Air, and let the Smoke pass, and the force of the Smoke which goes off is encreased by the Narrowness and Length of the flues, and by the Number of Checks in them, and the Thickness or Clofeness of their Sides, or what defends it from the Cold, as in Gunpowder, &c. So the force of Steam raised from a Fluid by Corpufcles of fire pervading the Pores of that which contains it, or by fermentation

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