jectile force, the velocity of the body is increased, and therefore it continues the longer in motion; because in proportion to the quantity of the air that is pushed away, and the Sollicito motu femper jactatur, eoque Verberat annellum dubio procul, iret ut intus Here he tells us, that the air furrounds and lies hid in pores of all bodies; and that the air which lies hid in the pores of the steel, is in continual motion forwards, and so strikes upon the ring as if it would enter it, and cannot; and fo is carried towards that part which is rendered most void and empty.-An Hutchinfonian, was he to write in Latin, could fcarcely exprefs his fentiments more fully. And further, to convince us that he uses the words vacuum and inane only for rarior aer, and not in the modern sense of them, let these two lines speak. Can Et quafi multa brevi fpatio fubmittere debet Lumina fol, ut perpetuo fint omnia plena. 7. 4. Edit. Nardii, 1647. "The fun ought to emit many rays in an inftant, that "there may be kept up, perpetually, an abfolute plenum." any words be more decifive for a plenum? The word vacuum feems to be derived from the Hebrew, 7p to kindle, burn, melt, diffolve, (viz.) the grains into atoms, and fo make them more ready to give way, or make room for the spirit to come in, as if the place was empty. Horace calls the air a vacuum; expertus vacuum Dædalus aera. Ode 3. 1.1. 1. 34. U 2 to to the force with which it is pushed away, the longer time it will take in returning into, and fo filling up the vacuum; or the longer the mixture will be in becoming equal. And fo the preffures on all fides of the body are the longer in coming to an equilibrium.- -Thus, in the firing of cannon, the air is divided by the action of the fire to a great degree, and to a great diftance; and the grofs particles are drove away with a prodigious force, fo as to break windows at fome diftance. And I have been informed by a gentleman present in our late wars in Flanders, that men have been beat down by the blaft or waft of the ball in its course; that is, as I fuppofe, by the air pushed away on each fide to make way for the ball. And the heated or fired air behind, which makes the vacuum, and into which the spirit pushes and drives the ball, pursues it for fome time, in the likenefs, as I take it, of a faint blue flame, like that of a candle. But then this vacuum, by not being renewed by a fresh action of fire, or otherwise, to thin and divide the air, is gradually filled by the neighbouring parts of of grofs air coming in; and fo the motion at length ceases. For the mechanism of the heavens is fuch, that it attempts to restore the balance or equilibrium of the air, where-ever it is deftroyed; and when the equilibrium is restored, motion can no longer continue. But this can never happen or be the cafe at the hinder part of the earth; fo there will always be a draught of fpirit, fo an uniform accelerative force, and fo motion. And this will be kept up and renewed by the columns of light and spirit, which the earth in its progreffion conftantly turns behind: and so there will always be a force able to impel the earth, and overcome the resistance before. For as faft as the fpirit attempts to reftore the balance or equilibrium, by rushing into the light or rarefied air behind, the balance is destroyed by a fresh supply of fine æther or light being brought to it by the column of light turned behind the earth in its progreffion; and fo this continual struggle to restore the equilibrium, preserves a continual impulse behind, and perpetuates the motion of the earth. And this vacuum will be in proportion to the the size of the globe to be moved: for the larger and folider it is, the larger will be the column or pillar of light on the fide next the fun, and of fpirit on the opposite fide which it interrupts; and the larger the pillar of light which is interrupted, the greater will be the vacuum which is made by that pillar of light fo interrupted, and turned behind, as the globe is moved forward; and the greater the vacuum, the greater and stronger will be the draught; and the larger the pillar of spirit which is interrupted by the globe on the fide oppofite to the fun, the more grofs air will be there ready and proper to rush in, and fupply the draught. THE means therefore neceffary to move. a body in the firmament or airs, and to continue its motion, are a thinned fpace, or place full of light, or a vacuum, behind the body, for the spirit or grofs air in motion to rush into and impel, and a conftant renewal of the vacuum to continue the impulse, and so motion. And this is effected by the pillar of light, or air rarefied, and in agita tion, being continually turned behind the earth; which, as already obferved, will make the impulfe behind much stronger than the refiftance before; because the air before the earth is in its common condition, or mixture of light and fpirit, and can eafily be pushed away, and recede through the column or pillar of light intercepted by the hemisphere of the earth next the fun, and fo turn into the vacuum, or thinned air behind the earth, and heighten the action of the N, or fucking in of the spirit there. I think the wind-gun will ferve as a proof of the different effect of the air in its ordinary condition, when the light and fpirit are mixed together, as they are before the earth; and when the air is mostly in grains or grofs maffes, or is condenfed, as they call it, as is the ftate of that air which rushes into the vacuum, or thinned or rarefied æther behind the earth, and impels it on its western fide. And it will also fhew, how eafily the refiftance before is overcome by the impulse behind. Now, I muft ob-" ferve, that the condenfation of the air, in the |