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of the forms of organixed lifa ultimately decay, and are resolved into inorgunie aggregates; and the same elementary substances, differently arranged, are contained in the inert soil, or bloom, and emit fragrance in the flower; or become, in auimals, the active organs of inind and intelligence. du artificial operations, changes of the same onler occur: substances having the characters of arth, are converted into metals; clays and sands are united, so as to become porcelein; earths and alkalies are combined into glass; acrid and corrosive bodies are furuncatiom tasteless substances; ro. Jours are fixed upon siutl's, or changeil, or madle to disappear; and the productions of the enteral, vegetable, and animal hing dumns, are converted into new fouins, and made subservient to the purposes of chixed life. To frace, in detail, their diversitive and complicated phiæ nomena, to arrange them, and dedice general laws fruin their analogies, is the business of Chemistry."

507. The ancients conceived that there were but four elements, or first principley---Air, Water, Earth, and Fire.

The moderns have analyzed these four elements, and have discovered other elements of those elements, viz. Oxygen, Hydrogen, Nitrogen, Chlorine, Carbon, Caloric, (or atomic motion) Sulphur, l'hosphorus, nine Earthis, and twenty-eight Metals,

Obs. 1.Almospheric Air is now found to be a com pound of Nitrogen or droles and Oxygen, which are preserved in a gaseous state by Calone.

WATER is found to be a compound of Orygen and Hydrogen i

Earth is a compound of mine different substances, now called Earths. (See 321.)

And I'ur is found to consist of mere atome motian,

2.- The forms of martor are i ell arranged into three distinct classes, by Sir 11. Davr. The first class consists of soleilha whirla compose the grent koowu part of the globe. Solid bodies, when in small masses, retain what

ever mechanical form is given to them: their parts are separated with difficulty, and cannot readily be made to unite after separation; some solid bodies yield to pressure, and do not recover their former figure when the compressing force is removed, and those are called nonelastic solids : others, that regain this form, are called dlastic bodies. Solids ditter in degrers of havdness; in colour: iu degrees of epocity or try trency: in density, or in the weight afforded by equal volarnes; and when their forms are regular or ervslallized, in the nature of these forms,

The second class consists of equids, of which there are much fewer varieties. Liquids, when in small masses, assume the spherical form; their parts possess freedom of motion; they differ in degrees of density and tenacity; in colour and degrees of opacity or transparency. They are usually regarded as incompressible; at least a very great mechanical force is required, to make them occupy space perceptibly smallet.

"The third class, elastic Nuids or gases, exist free in the atmosphere; but they may be contiued by solids, or by solids and fluids, and their properties examined. Their parts are easily moveable; they are compressible and expansible; and their rolumes are inversely, as the weights compressing them. All known elastic fluids are transparent, and present only two or three varieties of colour; they differ materially in density

3.-Besides these forms of inatter, which are easily sul. mitted to experiment, and the parts of which may be considered as in a state of apparent rest, there are other foras of matter which are known to us only in their states of motion when acung upon our organs of seuse, or upou other matter, and which are no: susceptible of being confined. They have been sometimes called ethereal substances, which appears a more umexceptionable name than imponderable substances. It cannot be doubted that there is matter in motion in the space between the sun, the stars, and our globe; though it is a subject of dis cussion, whether successions of particles be emitted from these heavenly bodies; or motions communicated by skem, to particles in their visimity, and transmitted by

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wewensive impulses to other particles Bharval watter ditore, either in te gatune, aw in ita attor hona, fom in** tion for it produces diferent eifeula adiant heal aud different kinds of light

SON. Caloute, say many ohemiata, in a more Name of that element or principle, which, don Bened with various hodles, produces the sensation of heat, but, according to the theory of Sir Richard l'hillips, there is no mehrlernent, and all the phenomena are mere elleota of ATOM TO NOTIONS

Ons 1,- Body, says he, la ansceptible of two varieties op motioni (1) a motion or imple of an aggregate, which occasione it to change its place in regani to other Aggregates; and (2) a motion of the stones of an ageragate, created when any impulae fom any online casuot produce commentantrale change of place in the usgregate and dimine the motion, sollimi, by no action, the impulae terminala within the body in the mutual actions of ile component stons

2.--Motion of both kinda, Naya Sir R. Phillipa, 000inues to affect a boly, until it has been imparted or transferred to aggregates in ontact, or has been dimused or radialed throwlithe monitium in which it is imineraedi and this law of the qualidation of the went wi af noving aggregates and acqua with the bike pole of receiving and diffining the motion, is the proximate cause of all varieties of material phenomena

3. Morion appeara, therefore, 10 conatitude the life, power, and energy of matters and is the active soul of the Universe Matter in ita palicu, ani dhe pelative penge : mene of bodies are the ponude, Asit Bola ou Aggregatet by contact, or by impulse, on and downlı modia, il con atitudes the object of PAweat l'holocephy, and, as it al fecta compounds or structures of Atoms, it is the obiel of Chemical Parlosophy.

4.- Wheu percussion or collision does not produce un punt yuanuty of aggregate motion in proportionate olange of place in the arrogate, or when the wution

revived cannot be tranaferred by diffusion, as when a piece of iron, laid on an anvil, receives the motion of a hammer, or when two piece of wood are rubhod together, au lutestine re-action of the atoms in the iron and woud takes place, accompanied by the perception of heat, and by a series of phenomena depending on the gnantity of motivu tbus eoneontrated, and on the acceleration ul the mame by reiterated blows, rubbings, or transfors of motion.

3. This intestine motion produces varlous phenomena of the several component atoms of the affected body in regard to one another, and to the heterogeneous media in wbich they are situated : thus, one quantity creates a perception of heat, another sensibly imparts that peroep un to the atoms of the surrounding media, another con. vures the fixed mass into fluida, au aceeleration converts the duud, iuto diverging gas, and a further acceleration, which exceods the radiating powera of the surrounding media, decomposes those meilia, exhibiting flame and intense hear, in the solidification of the oxygenous part of the media, and producing aubtle radiations on the rare medinm which tills space, thereby affecting the norves of the eye, imbued with that medium, with the perceptions

6.-The parting with each degree of atomie motion produces a contrary series of plavuomena i thus gas, ou parting with its heat or atomio motion to orber bodies, becomes liquid, and liquida, by parting with their brat or excited motion, become solide; and the diffusion of hea or atomie metion on such re-conversion is aensible, when the oxygenous part of atmospheric air, solidified by re piration, gives ont what is called animal heat; and when the same, solidified by combustiou, or reduced in volume by cno pression, gives out neai, and excites the pulsations of light. Philips's Synopsis

7.--When any body (saya SIRH DATY Is cooled, i ocenples a smaller volunie than before; it is evident, therefore, that its parts must have approached towarda ench others when the body is expanded by beat, it is equally evident that its parts must have separated from each other. The immedite cause of the phenomena of hrai, than, is mutton, and the laws of its communiention

are precisely the same as all the taws of the communication of motion,

Since all matter also may be made to occupy a smaller volume by cooling, it is evident that the particles of matter must have space between them; and since every body can communicate the power of expansion to a body of a lower temperature, that is, can give an expan. sive motion to its partieles, it is a probable inferenee that its own particles are possessed of motion ; but, as thera is no change in the position of its parts as long as its tem, perature is uniform, the motion, if it exist, must be a vibratory or undulatory motion, or a motion of the particles round their axis, or a motion of particles round cach other.

It is possible to account for the phenomena of heat, If it be supposed that in solids the particles are in a constant state of vibratory motion, the particles of the hot test bodies moving with the greatest velocity, and through the greatest space; that in Auids, and elastic fluids, besides the vibratory motion, which must be conceived greatest in the last, the particles have a motion round their own axis, with different velocities, the particles of elastic fluids moving with the greatest quickness; and that, m ethereal substances the particles move round their own axis, and separate from each other, penetrating a right lines through space.

Temperature may therefore be conceived to depend upon the velocities of the vibrations, increase of cits pacity on the motion being performed in greater space; and the diminution of temperature during the evuvérsia of solids into liquids or gases, may be explained on the principle of the loss of vibratory motion, in consequence of the revolution of particles round their axis, at the mofaent when the body becomes fluid or æriformu, ar frona the loss of rapidity of vibration in consequence of the notion of the particles, Dary's Chemistry,

8.-In fine, says Sir R. Phillips, Molions of matter subject to regular mechanical laws, acting absolutely or

ubordinately, generally or locally, on aggregates os Hows, and producing various densities and different de trees of locomotion and afinity in atoms of matter of Liliereat sonstituent forma, are the proximate crusan dal

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