the amazing velocity of 12 millions of miles in a minute, they would tear in pieces the tender coats of the strongest eye. From this infinite divisibility of matter,* we deduce the surprising corollary: viz. That it is possible, that any given particle of matter, however small, may be formed into a sphere, that shall fill any given space, however large, and yet not leave a pore in the whole, that shall exceed a given magnitude. That matter is CAPABLE OF BEING MOVED or translated from one place to another, none have ever seriously denied; not even the cartesians, who notwithstanding assert, that there is no such thing in nature as a vacuum. This property of matter, which is so evident to all our senses, necessarily proves that there must be some space void of all matter: for when a body moves, it must be either through a space absolutely full of matter, or a vacuum; or at least the motion must be in a circle. If the first be asserted, then two bodies may be in the same place at the same time; which is absurd, and contrary to all our ideas of matter: and the last is contrary to all our experience; and therefore there must be such a thing as a va cuum. The VIS INERTIA of a body, which may be termed its resistance, is that property, whereby it endeavours to continue in its state of motion or rest, and resists the actions and impressions of all other bodies, which tend to generate or destroy motion in it. This * The infinite divisibility of matter is to be considered as only existing in the mind, where it may indeed be divided into a number of parts greater than any that can be assigned. And the difficulty of conceiving of this proposition is no solid objection to its truth. property does not depend upon its gravity or tendency to its proper center. For if there were but one body in the universe, it would require a certain degree of force to put it in motion, and the same to destroy that motion again: and whether it be acted upon by gravity or not, it will, when put in motion, pass over the same space in a given time in the direction of the impressed force; for otherwise the effect will not be proportional to the moving force; which must always be the case. ATTRACTION and REPULSION are properties of bodies, whereby they accede to, or recede from, each other. This property was originally given to matter by the omnipotent power of God, and does not seem necessary to its existence. We do not presume to assign the cause of this property, but only to prove its existence and reality, in all the bodies that fall under our notice. Various hypotheses have been formed by ingenious philosophers, to account for this strange phenomenon; but as they are all unsupported by experiment and observation, they should have no place in a system of philosophy, which appeals to demonstration and experiment. We cannot indeed conceive of a body acting where it is not, any more than of its acting after it has ceased to exist; and therefore it is supposed that there may be some subtile and elastic medium diffused through our whole system, and pervading the pores of all bodies, by the tremors and undulations of which the attractive and repulsive virtue of bodies is excited and propagated from one to another. But however this may be, it is our business at present only to explain the effects and laws of its operation. In order to which we observe,-That any power or virtue proceeding from a body, in right lines and in all directions, must decrease in its strength and in whose diameter is but one half of that quantity. This is a necessary consequence of that law,-That the power of attraction is proportional to the quantity of attracting surface in contact with the fluid. Now according to this law, the smallest tube can raise but half the quantity of fluid suspended by the other, as the number of the particles in its internal circumference is but half the number of particles in the other. But the altitude of the fluid in the lesser tube must be just double to what it is in the larger, in order to have the quantity in the lesser tube just one half of what it is in the larger; as the quantity increases with the square of the diameter. The whole fluid in the tube is suspended by the attractive force of a ring of particles in the tube near the surface of the fluid, as the lower parts of the tube draw the fluid as much downwards as upwards; so that it is of no consequence, what the form of the immersed part of the tube may be, whether straight or crooked, wide or narrow. This ring of particles having a determinate force of attraction, can suspend only a certain quantity of the fluid, whose gravity is an exact counterpoise to the attraction of the tube. Hence the decreasing velocity of the ascending fluid, as the quantity raised gradually approaches nearer to an equality with the attractive force of the tube. The same principle accounts for the form of the hyperbolic curve in the water rising between two glass planes set together in a small angle; as every column may be considered as a capillary tube, differing in diameter from the contiguous column, according to its distance from the angular point of the planes. The capillary syphon works by the same laws, that are observed in a capillary tube, raising the fluid to the bend of the syphon, by the force of corpuscular attraction; and the same power continuing to exert its energy in conjunction with the gravity of the fluid, causes the fluid to descend through the longer leg of the syphon till the whole be decanted. The philter is only a compound capillary syphon, the threads of which it consists lying near together form long slender vacuities, resembling so many capillary tubes, which attract and raise the fluid. The wick of a candle or lamp is no other than a philter, which attracts the particles of oil or melted tallow. Such also are the tubular fibers in the roots of trees and vegetables, which act as so many philters, attract the moisture of the earth, and imbibe the nutritive juices destined for the growth of vegetables. Thus also the fine ramifications of the lacteal, lym phatic and sanguiferous vessels, disposed through all the substance of the glands and viscera, are so many fine capillary tubes, which assist the circulation of the blood and juices in an animal body, in order to their various secretions; which is an effect supposed vastly too great for the pulsive force of the heart. Hence too, the more subtile parts of medicines, used for the cure of diseases, are incorporated with the juices of the body, being attracted and carried to the remotest members by the force of these capillary tubes. Thousands of these vessels terminating in the pores of the skin, conduct the juices to the surface of the body, where they must be expressed by the action of the solids, and appear on the skin in large drops of sweat, or being greatly rarified by the natural heat of the body, are attracted by the air, and carried off in an imperceptible vapour, called the insensible perspi ration. The motion of a drop of oil towards the angular the amazing velocity of 12 millions of miles in a minute, they would tear in pieces the tender coats of the strongest eye.. From this infinite divisibility of matter,* we deduce the surprising corollary: viz. That it is possible, that any given particle of matter, however small, may be formed into a sphere, that shall fill any given space, however large, and yet not leave a pore in the whole, that shall exceed a given magnitude. That matter is CAPABLE OF BEING MOVED Or translated from one place to another, none have ever seriously denied; not even the cartesians, who notwithstanding assert, that there is no such thing in nature as a vacuum. This property of matter, which is so evident to all our senses, necessarily proves that there must be some space void of all matter: for when a body moves, it must be either through a space absolutely full of matter, or a vacuum; or at least the motion must be in a circle. If the first be asserted, then two bodies may be in the same place at the same time; which is absurd, and contrary to all our ideas of matter: and the last is contrary to all our experience; and therefore there must be such a thing as a va cuum. The VIS INERTIA of a body, which may be termed its resistance, is that property, whereby it endeavours to continue in its state of motion or rest, and resists the actions and impressions of all other bodies, which tend to generate or destroy motion in it. This * The infinite divisibility of matter is to be considered as only existing in the mind, where it may indeed be divided into a number of parts greater than any that can be assigned. And the difficulty of conceiving of this proposition is no solid objection to its truth. |