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“ Kindling former smiles again

“In faded eyes that long have wept.
. Like the gale that sighs along

6 Beds of oriental flowers,
6 ls the grateful breath of song

" That once was heard in happier hours,
* Fili'd with balm the gale sighs on,

66 Tho' the flowers have sunk in death, 66 So when pleasure's dream is gone,

6. Its memory lives in Music's breath.” T. MOORE.

XXIX. Of Physics; or, the General Properties

of Matter. 634. All existence is, what it appears to be to the powers of our senses ; and is, therefore, relative, or comparative, to those powers.

Obs. 1.--Thus there is no intrinsic sweetness in sugar; but the quality of sweetness is in the sense of the palate. In a violet, there is no inherent colour; but the sense of colour called violet, is in our optic nerve; and the smell of sweetness produced by the same flower, is in the olfactory nerve.--So there is no sound in a vibrating string; but the sound, so called, is the vibrating effect produced on our auditory nerves.

and the sense of hardness, or substance in a stone, arises from its being harder than our fingers, which have not power to pass through it. It has been a favourite notion of ancient and modern philosophers, that the substratum or basis of all matter is the same; and that all the varieties exhibited to our senses, are only so many modifications, capable of producing their respective sensible effects.

2. A person born blind, has no proper idea or conception of colours: he can feel the hardness, the roughness, and the length and breadth of surfaces; but he can have no preception of their various colours.--So one born deaf, sees the motion of a bow on a violin, of the sticks on a drum; but has no idea of their sound.--In like manner, all food is alike, in flavour, to those who have lost their sense of taste and smell.

635. The sensations produced by things out of ourselves, are called our perceptions; and the property or power of bodies to excite or create particular perceptions, is, in common language, considered as the perception itself; and the body is considered as possessing the sensation itself, which it usually creates in

us.

Obs.--Thus, we call vinegar sour, oil smooth, and fire hot ; though the sense of sourness, smoothness, and heat, is in us, not in the bodies which create those perceptions. So, likewise, in common language, we talk of the motion of :he sun, and stars ; though it is only our earth that moves.

636. Every collection, then, of properties, capable of effecting our senses, is called material or matter; and it possesses extension, or bulk; solidity, or the power of maintaining its space; and divisibility, or the capability of being divided into infinitely small parts.

Obs. 1.--Extension is infinite ; at least, the human mind can set no bounds to it, but can add millions to millions of miles in every direction.

2. Solidity is a relative idea ; and is measured by us in the ratio of the attraction, or centripetal force of the earth, called soeight or gravitation. A cubic foot of platina weighs as much as 92 cubic feet of cork, or as 230,000 cubic feet of hydrogen gas; yet the platina itself may be light compared with other bodies unknown, and the cork and the gas be heavy in regard to others.

3. The property of infinite divisibility will be evident from the consideration that every particle of matter, however small, must have an upper and an under side. T'he infinite divisibility of matter is proved by the formation of animalcula, already treated of, and by the malleability of gold. Scents are equally subtle; and it is computed, that the millionth part of a grain of musk divides itself into seven quadrillions of parts, in scenting a room. So, also, the light generated by a single grain of tallow, diffuses itself over a space two miles round, but it is doubted whether light is more than an undulation

637. The followers of Sir Isaac Newton also ascribe to matter an innate principle of attraction for matter, and assert, that all matter attracts all matter at equal distances in proportion to the respective quantities. But a late writer, Sir Richard Phillips, maintains that the phenomena ascribed to innate attraction, is a

mere accident of matter arising from transferred mom tions, of which all matter is the patient.

Obs.—Sir Richard Phillips, in his “ Essays on the Prosi. mate Causes of the Phenomena of the Universe," observes, that Sir Isaac Newton first assumed and admitted the gener. ally ad pred principle of innule attraction as a specific cen tral force; and then, invented another force to counteract it, which second force he considered as acting on the planets simultaneously at right angles to the other, giving it the name of projectile force. These two forces he adopted as realities in nature, and to perpetuate the latter, he conceived space to be a vacuum.

nstead, however, of a system which has introduced into science such fanciful and arbitrary forces, Sir Richard Phillips is desirous of establishing a system of forces arising from the universal and analogous principle of MOTION, as it is transferred, by various combinations, from the greatest to the smallest portions of matter. He asserts that all phenomena of matter are mere effects of transferred MOTION; and, that known motions are competent to produce all phenomena.

Motion, he says, is that universal principle which confers on masses of maiter the power of acting on other masses. In regard to matter, which is essentially inert, it is the source of momentum, or potentiality, and is the animating soul of the material Univers SPACE is the stage, VATTER is the subject, and Motius is the agent, producing all phenomena. Motion

appears, says he, to be the proximate agent of OMNI. POTENCE, and to be necessarily a direct emanation from the primary and eternal source of all power.

2. Instead of the words attract and repel, which lead, says Phillips, to false notions of causes, he

proposes to substituto the words to accede and to discede ; and for attraction, accision; and for repulsion, discission, as expressing the mere acts of falling towards, and separating from. Instead also, gravitate or gravitation, he proposes to introduce, centripetate and centripetation.

3. Sir Richard then proceeds to show that a stone which has been let fall to the earth is the patient of the twofold mot ons of the earth, the rotatory and orbicular; and that these motions acting as forces on the stone, are competent to occasion it to fall to the earth. From this fact he deduces the following general conclusions :

That every body on the earth which has had any new direction of force given to it, is nevertheless subject to the permanent influence of the pre-existing orbicular and rotatory forces in the combined lines of their direction, and that the

resulting line of motion in falling is the effect of all the operative forces.

That it is the necessary tendency of the rotatory motion to give an equal momentum to the heterogeneous masses composing a planet and its atmosphere, while the whole are moved, by a common force, with an equal veloeity in the orbit.

'l hat the force with which the deflection by the rotatory motion is produced, is as the density of the body deflected to the density of the medium in which it moves, and in the inverse ratid f the squares of the distance from the centre.

That, therefore, the phenomena, hitherto ascribed to an inpate, occult, universal power, called Gravitation, are simple results of known local motions.

That of course, the laws which apply to the earth apply to the same classes of phenomena in all planets; and it may be inferred, generally, that the phenomena of aggregation, consolidation, and local motion, in all planets, result from their two fold motions around their own axis, and around their primary

4. There is, says Sir R. a centripetal force, or tendency towards the centre but it does not arise from any innate principle, or from any tendency as a tendency; but from mechanism, easily analysed an, understood ; and applicable to every variety of the phenomena. The general results olay correspond, but it is not indifferent whether we ascribe them to a true or false cause, or whether we argue on a true or false analogy of the causes and effects. Thus it appears, that the projectile force of Newton is unnecessary, because, if there be no universal centripetal force, there is no necessity for a constant centrifugal force to counteract it; and we thus remove an opprobriun from philosophy,

638. The motions of the planets in their orbits, Sir Isaac Newton ascribes to a projectile force in a right line given them at their creation, from which right line they are drawn into curvilinear orbits by the force of gravitation to the sun.

And that the projectile force may not be din inished by resistance, he supposes

the

space in which they move to be a vacuum

or void.

639. On the other hand, Sir Richard Phillips considers space to be filled with a gaseous medium, and he describes the planetary motions as being produced by the action or impulse of the sun on and through tha

medium; it being a fact, that the sun moves around the centre or fulcrum of the masses of which the solar system is composed.

Obs.---The phenomena of the universe appear therefore to be results of a system of MOTION

transferring MOTION, or of Motion generated by Motion. By this simple and intelligible agency, a stone is propelled to a planet by the motions of ibe planet-a planet is carried round the sun by the motions of the sun—a secondary is carried round a primary by the

in: motions of the sun and primary-and the motions of the suo are, perhaps, caused by the motions of systems of sudswhile the motions of those systems may again be caused by other superior motions! In short, all nature consists of a se. ries of included motions, produced by the motions of superior bodies and systems, till we ascend to the first term in the series to an inscrutable CAUSE of CAUSES!

640. The laws of force are the same, whether the phenomena are produced by the principle of innate attraction, or by accidents of motion, i. e. the force is inversely as the square of the distance, and directly as the quantities of matter. See my Grammar of Natural Philosophy.

Obs.-- Accelerated motion, in falling bodies, is created by new impulses of contripetal force, acting on a body already possessed of a given motion and which acts at every instant, as though no motion were already acquired. The motion isą as the square of the times employed in falling. Thus

Seconds of time, 1, 2, 3, 4, 5, &c.
Their squares

1, 4, 9, 15, 26, &c. Feet of motion, 16, 64. 144, 256, 400, &c. 2. The exclusion of all other active forces from nature, except the palpable one which arises from Motion, as transferred, transmitted, and reflected from body to body, not

aly simplifies our views of nature, but furnishes many new illustrations of natural operations. Thus, as all motion results from motion, it would appear, that animal motions are not created by their will, but that the will merely transfers part of the motions of the earth to certain parts of the body. If the will direct the motion of the hand, the will serves merely as a fulcrum from the foot, which is connected with the moving earth, to the hand to which the energy of the foot is conveyed, as by a lever. So of all other motions, however complicated and diversified, they may be traced te greater motions, as their origin and source. In a word,

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