Plastic. occurred to a writer who does not appear to have borrowed it either from the Lyceum or the Academy.

This writer is Mr Young, of whose active substance, and its agency in moving bodies, some account has been given elsewhere, (see MOTION). As a mere unconscious agent, immaterial, and, as he expresses himself, immental, it bears a striking resemblance to the plastic na ture or vegetable life of Cudworth: but the author holds it to be not only the principle of motion, but also the basis or substratum of matter itself; in the production of which, by certain motions, it may be said to be more strictly plastic than the hylarchical principle, or vis genitrix, of any other philosopher with whose writings we have any acquaintance. Though this opinion be singular, yet as its author is evidently a man who thinks for himself, unawed by the authority of celebrated names, and as one great part of the utility of such works as ours consists in their serving as indexes to science and literature, we shall lay before our readers a short abstract of the reasonings by which Mr Young endeavours to support his hypothesis, and we shall take the liberty of remarking upon those reasonings as we proceed. The author, after a short introduction, enters upon An Essay his work ‡, in a chapter intitled, Analysis of Matter in on the pow-general. In that chapter there is little novelty. He ers and mechanism of treats, as others have done, of primary and secondary nature. qualities, and adheres too closely to the language of Locke, when he says, that "the nature of bodies signifies the aggregate of all those ideas with which they furnish us, and by which they are made known." To say the best of it, this sentence is inaccurately expressed. An aggregate of ideas may be occasioned by the impulse of bodies on the organs of sense, but the effect of impulse cannot be that which impels. We should not have made this remark, which may perhaps be deemed captious, were we not persuaded that the vague and inaccurate use of terms is the source of those mistakes into which, we cannot help thinking, that the very ingenious author has sometimes fallen. Having justly observed, that we know nothing directly of bodies but their qualities, he proceeds to investigate the nature of solidity.

"Solidity (he says) is the quality of body which principally requires our notice. It is that which fills extension, and which resists other solids, occupying the place which it occupies; thus making extension and figure real, and different from mere space and vacuity.

If the secondary qualities of bodies, or their powers va- Plastic riously to affect our senses, depend on their primary qualities, it is chiefly on this of solidity; which is therefore the most important of the primary qualities, and that in which the essence of body is by some conceived to consist. This idea of solidity has been judged to be incapable of any analysis; but it appears evident to me (continues our author), that the idea of solidity may be resolved into another idea, which is that of the power of resisting within the extension of body. Hence it becomes unnecessary, and even inadmissible, to suppose that solidity in the body is at all a pattern or archetype of our sensation."

That solidity in the body, and we know nothing of solidity any where else, is no pattern of any sensation of ours, is indeed most true, as we have shown at large in another place, (see METAPHYSICS, No 44 and 171): but to reconcile this with what our author asserts immediately afterwards, that "solidity is no more in bodies than colours and flavours are, and that it is equally with them a sensation and an idea," would be a task to which our ingenuity is by no means equal. He affirms, in deed, that solidity, as it is said to be in bodies, is utterly incomprehensible that we can perfectly compre. hend it as a sensation in ourselves, but that in bodies nothing more is required than a power of active resistance to make upon our senses those impressions from which we infer the reality of primary and secondary qualities. This power of resistance, whether it ought to be called active or passive, we apprehend to be that which all other philosophers have meant by the word solidity; and though Locke, who uses the words idea and notion indiscriminately, often talks of the idea of solidity, we believe our author to be the first of human beings who has thought of treating solidity as a sensation in the mind.

Though it is wrong to innovate in language, when writing on subjects which require much attention, we must, however, acknowledge it to be unworthy of inquirers after truth to dispute about the proper or improper use of terms, so long as the meaning of him who employs them can be easily discovered. We shall, therefore, follow our author in his endeavours to ascertain what this power of resistance is which is commonly known by the name of solidity. All power he justly holds to be active; and having, by an argument (A) of

which

Plastic. which we do not perceive the force, attempted to prove that it is by an inward power, and not by its inertia, that one body prevents another from occupying the same place with itself, he naturally enough infers matter to be essentially active. "But the activity of matter is to be considered in a certain limited sense, and its inertness is to be regarded in another limited sense; so that these are compatible within their respective limits. The activity of body may be considered as belonging to the parts of a compound; its inertia as the inertia formed of those parts. The actions of the parts are everywhere opposed to each other, and equal; and hence results the inactivity of the whole."

SOLIDITY alone of the primary qualities being positive, and peculiar to bodies, and our author having resolved this into ACTION or POWER, it follows, by his analysis, that the ESSENCE OF BODY is reduced to power likewise. But, as he properly observes, power is an idea of reflection, not acquired by the senses, but suggested by thought. Hence our knowledge of real existence in body must be such as is suggested to us by our thoughts exercised about our sensations. "We are capable of acting and producing changes in appearances; and this faculty, which we experience to exist in ourselves, we call power. We are conscious of the exertion of our own power; and, therefore, when we see ACTION OF CHANGE happen without any exertion of ours, we refer this to other powers without us, and necessarily conclude the POWER to exist where the change begins or the action is exerted. This power, then, referred to bodies, must exist in them, or it can exist no where."

In two chapters, which might easily have been compressed into one not so long as the shortest of them, our author analyzes atoms or the primary particles of matter, and strenuously opposes their impenetrability. He allows that there are atoms of matter not divisible by any known force; but as these, however small, must still be conceived as having extension, each of them must be composed of parts held together by the same power which binds together many atoms in the same body. This power, indeed, he acknowledges to operate much more forcibly when it cements the parts of a primary atom than when it makes many atoms cohere in one mass; but still it operates in the same manner; and as the ideal analysis may be carried on ad infinitum, the only positive idea which is suggested by atoms, or the parts of atoms, is the idea of a resisting power. That this power of resistance, which constitutes what is vulgarly called the solidity of bodies, may not be absolutely impenetrable, he attempts to prove, by showing that resistance does in fact take place in cases where impenetrability, and even solidity, are not supposed by any man.

"Let us endeavour (savs he) to bring together two like poles of a magnet, and we shall experience a resistance to their approximation. Why, then, may not a piece of iron, which between our fingers resists their coming together, resist by an efficacy perfectly similar, though more strongly exerted? If magnetism were to act upon our bodies as opon iron, we should feel it; or were VOL. XVI. Part II.

magnets endowed with sensation, they would feel that Plastic. which resists their nearer approach. The resisting extension between the two magnets is permeable to all the rays of light, and reflecting none is therefore unseen; but it is easy to conceive that the same power which resists the approach of the iron might resist and reflect some rays of light. We should then have a visible object interposed between the two magnets, as we have before supposed it might be a tangible one. It is likewise easy to conceive that which is tangible and visible so applied to our organs of tasting, of smelling, and of hearing, as to excite ideas of flavours, odours, and sounds. Thus we see that an action, in which no supposition of solidity or impenetrability is involved, may be conceived to assume all the qualities of matter, by only supposing a familiar effect extended in its operation."

This reasoning is exceedingly ingenious, though perhaps not original; but what is of more importance, it does not approach so near to demonstration as the author seems to imagine. If magnets operate by means of a fluid issuing from them (see MAGNETISM), those who hold the solidity or impenetrability of matter will maintain, that each atom of the magnetic fluid is solid and impenetrable. That we do not see nor feel these atoms, will be considered as no argument that they do not exist; for we do not see, nor in a close room feel, the atoms of the surrounding atmosphere; which yet Mr Young will acknowledge to have a real existence, and to be capable of operating upon our senses of hearing and smelling. Let us, however, suppose, that by this reasoning he has established the non-existence of every thing in the primary atoms of matter but active powers of resistance, and let us see how he conceives the actions of these powers to constitute what gives us the notion of inert and solid body; for that we have such a notion cannot be denied.

TO ACT he allows to be an attribute, and justly observes, that we cannot conceive an attribute to exist without a substance. "But (says he) we have traced all phenomena to action as to a generic idea, comprehending under it all forms of matter and motion as species of that genus. By this analysis, that complex idea we have usually denominated matter, and considered as the substance or substratum to which motion appertained as an attribute, is found to change its character, and to be itself an attribute of a substance essentially active, of which one modification of motion produces matter and another generates motion." The action of this substance Mr Young determines to be motion, (see MOTION, N° 16.); and he proceeds to inquire by what kind of motion it produces matter, or inert and resisting atoms.

"Whatever portion of the ACTIVE SUBSTANCE is given to form an atom, the following things are necessary to be united in such portion of active substance : 1st, It must in some respect continually move; for otherwise it would lose its nature, and cease to be active. 2dly, It must also in some other respect be at rest, for otherwise it could not form an inactive atom. 3dly, It must preserve unity within itself." The author's 4 K proof

Plastic. proof of the first of these positions we have given elsewhere. The second he holds to be self-evident; and the third he thinks established by the following reasoning: "Solidity is the result of those actions among the parts of any whole, whereby the unity of the whole is preserved within itself. Several uncobering things may be united by an external bond: this does not constitute these one solid; it may be one bundle; but if several things cohere, and have an unity preserved within themselves, they become one solid. An atom is the least and most simple solid."

Having thus proved the necessity of these three requisites to the formation of an atom, he observes, that the two first can only be united in a rotation of the portion of active substance about a centre or axis at rest. By such a motion, all the parts successively occupy different places in the orbit of rotation, and therefore move; the centre round which they revolve being at rest, the whole portion is also at rest; and thus the portion is at once moving and quiescent, as is required. The same kind of motion will also fulfil the terms of the third requisite; for a substance having a revolving motion around its own centre, preserves its unity by reason of all the parts preserving the same relation to the centre: and further, a motion of the active substance about a centre or axis will be an activity in the same orbit, which will act upon and resist whatever shall interfere to oppose its activity, or destroy the unity of the sphere, by diverting the course of the revolving motions. The activity or motion of a portion of ACTIVE SUBSTANCE about a centre will, therefore, give solidity to such portion; for it will give it unity and resistance, and in a manner tie together all the parts, forming them into one mass about their common centre: for they move or are active not towards the centre, in which case they would be lost in non-extension; nor from the centre, where they would dissipate in boundless space; but about the centre, preserving the same limits of extension: and being in this way active, they in this way resist any other activity opposed to them, that is, they resist any action which tends to penetrate or divide this sphere of revolving activity. Therefore, since any portion of active substance does, by revolving about a centre, become an united, resisting, and quiescent whole, the smallest portions of the ACTIVE SUBSTANCE which have such motions will become atoms, or make the smallest portions of matter."

Having thus shown to his own satisfaction how atoms of matter are formed, he next explains what at first he confesses may have appeared a paradox, "how the ACTIVE SUBSTANCE, retaining its own nature and essential properties, continuing immaterial, unsolid, and active, puts on at the same time the form of matter, and becomes material, solid, and inert. A sphere of revolving active substance, as it revolves continually about a centre, and as parts of the substance are considered as successively passing through every point in the orbit; considered thus in its parts, and in its motions, it is ACTIVE SUBSTANCE, immaterial, and unsolid; but the whole sphere, considered unitically, collectively, and as quiescent, is in this point of view a solid atom, material, and inert."

Such is the active substance of Mr Young, and such his theory of the formation of matter. That he has not with servility copied from the ancients, every reader of his book, who is not an absolute stranger to Greek

and Roman literature, will readily acknowledge; and Plastic yet if his theory be well founded, he has discovered a middle substance between mind and matter, more properly plastic than Aristotle or Plato, Cudworth or Berkeley, ever conceived. But truth compels us to add, that to us his theory appears to labour under insuperable objections. That there may be in the universe a substance essentially active, and at the same time not intelligent, is a proposition which we are by no means inclined to controvert. Various phenomena, both in vegetable and animal life, lead us to suspect that there is such a substance; but it does not follow that we are inclined to adopt our author's doctrine respecting the formation of matter. He conceives his proof, indeed, to be "in its nature not at all imperfect, or to fall short of demonstration; and if any one refuse it, he thinks it will be necessary for him to show, either that the explanation offered is not sufficient, or that some other expla nation will serve equally well."

To show that the explanation offered is not sufficient, will not, we apprehend, be a very arduous task; but we have no inclination to attempt ourselves another expla nation, because we believe that of the formation of matter no other account can be given than that which resolves it into the fiat of the Creator. That it cannot be formed by the motion of an immaterial substance in the manner which our author has very clearly described, seems to be a truth so evident as not to admit of proof; for if motion be, as he defines it, a change of place, every thing that is moved must have the quality of extension. But all the parts of this active substance which are given to form an atom, move round a centre, and are expressly said to occupy successively different places in the orbit of rotation. Every one of these parts, therefore, is an extended being: and since, according to our author, solidity is nothing but an active power of resistance, and the parts of this active substance, in their rotation round their centre, act upon and resist whatever interferes to oppose their activity, it follows that each of these parts is likewise a solid being. But, in the opinion of Mr Young himself, and of all mankind, whatever is extended and solid is material. This theory, therefore, exhibits a process in which atoms are formed of a substance, which, though it is said to be active, immaterial, and unsolid, appears, when narrowly inspected, to be nothing else than a collection of those very atoms of which the author pretends to explain the formation. Mr Young, who examines and very freely censures some of the doctrines of Newton and others, is too much a man of science to be offended at us for stating objections to a theory which is quite new, to a transformation which he himself acknowledges may to many "appear not only problematical and difficult to conceive, but wholly impossible, and implying contradictions absolutely and for ever irreconcileable." Whether this be a just character of it our readers must determine; but if we did not believe the author to be a man of ingenuity, we should not have introduced him or his work to their acquaintance.

PLASTIC Art, the art of representing all sorts of fi gures by the means of moulds. This term is derived from the Greek word #λaçın, which signifies the "art of forming, modelling, or casting, in a mould.” A mould in general is a body that is made hollow for that pur pose. The artist makes use of it to form figures in

bronze

It is in this manner, but with much practice and attention, that the artist forms, 1. Equestrian and pedes trian statues of every kind; 2. Groups; 3. Pedestals; 4. Bass-reliefs; 5. Medallions; 6. Cannons, mortars, and other pieces of artillery; 7. Ornaments of architecture, as capitals, bases, &c.; 8. Various sorts of furniture, as lustres, branches, &c. in every kind of metal and in the same manner figures are cast in stucco, plaster, or any other fusible matter. See PLASTER of Paris.

Wax being a substance that is very easily put in fusion, plastics make much use of it. There are impressions which are highly pleasing in coloured wax, of medallions, basso and alto relievos, and of detached figures; which, however, are somewhat brittle. But this matter has been carried too far: they have not only formed moulds to represent the likeness and the bust of a living person, by applying the plaster to the face itself, and afterwards casting melted wax into the mould; but they have also painted that waxen bust with the natural colours of the face, and have then applied glass eyes and natural hair; to which they have joined a stuffed body and limbs, with hands of wax ; and have, lastly, dressed their figure in a real habit; and by these means have produced an object the most shocking and detestable that it is possible to conceive. It is not a statue, a bust, a natural resemblance that they form; but a dead body, a lifeless countenance, a mere carcase. The stiff air, the inflexible muscles, the haggard eyes of glass, all contribute to produce an object that is hideous and disgustful to every man of taste. Figures like these offend by affording too exact an imitation of nature. In no one of the polite arts ought imitation ever to approach so near the truth as to be taken for nature herself. Illusion must have its bounds; without which it becomes ridiculous.

There is another invention far more ingenious and pleasing, which is that wherein M. Lippart, antiquary and artist at Dresden, has so much excelled. He has found the means of resembling, by indefatigable labour, great expence, and infinite taste, that immense number of stones, engraved and in camaieu, which are to be seen in the most celebrated cabinets. He has made choice of those that are the most beautiful; and, with a paste of his own invention, he takes from these stones an impression that is surprisingly accurate, and which afterwards become as marble: these impressions he calls pasti. He then gives them a proper colour, and incloses each with a gold rim; and by ranging them in a judicious order, forms of them an admirable system. They are fixed on pasteboards, which form so many drawers, and are then enclosed in cases, which represent folio volumes, and have titles wrote on their backs; so that these fictitious books may conveniently occupy a place in a library. Nothing can be more ingenious than this invention; and, by means of it, persons of moderate fortune are enabled to make a complete collection of all antiquity has left that is excellent of this kind; and the copies are very little inferior to the originals.

compass.

The proficients in plastics have likewise invented the art of casting in a mould papier maché or dissolved paper, and forming it into figures in imitation of sculpture, of ornaments and decorations for ceilings, furniture, &c. and which they afterwards paint or gild. There are, however, some inconveniencies attending this art; as, for example, the imperfections in the moulds, which render the contours of the figures inelegant, and give them a heavy air: these ornaments, moreover, are not so durable as those of bronze or wood, seeing that in a few years they are preyed on by the worm.

The figures that are given to porcelain, Delft ware, &c. belong also to plastics; for they are formed by moulds, as well as by the art of the sculptor and turner; and by all these arts united are made vases of every kind, figures, groups, and other designs, either for use or ornament.

From this general article the reader is referred to FOUNDERY, CAST, GLAZING, PORCELAIN, PAPIERMaché, POTTERY, DELFT Ware.

PLATA, the name of a very great river of South America, running through the province of Paraguay: whence the whole country is sometimes called Plata; though this name is usually bestowed only upon a part of Paraguay. In the latter sense it comprehends alt that country bounded on the east and south-east by the Atlantic ocean; on the south by Terra Magellanica ; on the west by Tucuman; and on the north, by the provinces of Paraguay Proper and Parana. The great iver La Plata, from which the country has its name, was first discovered, in 1515, by Juan Diaz de Solis; but denominated La Plata by Sebastian Gabato, from the great quantity of the precious metals he procured from the adjacent inhabitants, imagining it was the produce of the country, though in fact they brought it from Peru.

The country lies between 32° and 37° of south latitude. The climate is pleasant and healthy. Their winter is in May, June, and July, when the nights are indeed very cold, but the days moderately warm; the frost is neither violent nor lasting, and the snows are very inconsiderable.

The country consists mostly of plains of a vast extent, and exceeding rich soil, producing all sorts of European and American fruits, wheat, maize, cotton, sugar, honey, &c. and abounding with such excellent pastures, that the beasts brought thither from Spain are multiplied to such a degree, that they are all in common, no man claiming any property in them, but every 4 K 2

thens and Megara, and on the confines of Attica and Platze Megaris. Now in ruins.

Plata, man takes what he hath occasion for. The number of Plate. black cattle, especially, is so prodigious, that many thou

sands of them are killed merely for their hides, every time the ships go for Spain, and their carcases left to be devoured by wild beasts and birds of prey, which are also very numerous. Sometimes, when they cannot vend their hides, they will kill them for their tongues; and those who care not to be at the trouble to fetch them from the plains, may buy them for a trifle. There is a curious account in Lord Anson's voyage of the manner of hunting them on horseback; and of catching and killing them, by throwing a noose on their horns at full gallop, the horses being trained to the sport. Horses are no less numerous, and in common like the other cattle so that a man may have as many as he pleases for the catching; and of those that are already broke, one may buy some of the best, and of the true Spanish breed, for a piece-of-eight per head. Wild-fowl also is in great plenty here; partridges in particular are more numerous, and as large and tame as our hens, so that one may kill them with a stick. Their wheat makes the finest and whitest of bread; and, in a word, they seem to want for nothing here, especially the natives, but salt and fuel. The former the Spaniards have brought to them from other parts; and the latter they supply themselves with, by planting vast numbers of almond, peach, and other trees, which require no other trouble than putting the kernels into the ground, and by the next year, we are told, they begin to bear fruit. The return for European commodities is so great here, that it almost exceeds belief; an ordinary two-penny knife fetching a crown, and a gun of the value of 10 or 12 shillings 20 or 30 crowns, and so of the rest.

The river Plata rises in Peru, and receives a great many others in its course; the chief of which is the Paraguay. The water of it is said to be very clear and sweet, and to petrify wood; and contains such plenty and variety of fish, that the people catch great quantities of them without any other instrument than their hands. It runs mostly to the south and south-east; and is navigable the greater part of its course by the largest vessels, and full of delightful islands. All along its banks are seen the most beautiful birds of all kinds; but it sometimes overflows the adjacent country to a great extent, and is infested by serpents of a prodigious bigness. From its junction with the Paraguay to its mouth it is above 200 leagues. We may form some judgment of its largeness by the width of its mouth, which is said to be about 70 leagues. Before it falls into the Paraguay it is called Panama. See PANAMA.

PLATEÆ, in Ancient Geography, a very strong town of Bootia, in its situation exposed to the north, wind (Theophrastus); burnt to the ground by Xerxes (Herodotus, Justinus); mentioned much in the course of the Persian war: Famous for the defeat of Mardonius, the Persian general; and for the most signal victory of the Lacedæmonians and other Greeks under Pausanias the Lacedæmonian, and Aristides an Athenian general (Nepos, Diodorus, Plutarch); in memory of which the Greeks erected a temple to Jupiter Eleutherius, and instituted games which they called Eleutheria; and there they show the tombs of those who fell in that battle (Strabo). It stood at the foot of Mount Citharon, between that and Thebes to the north, on the road to A

PLATALEA, the SPOONBILL, a genus of birds be- Plate. longing to the order of gralla. See ORNITHOLOGY Inder. PLATANUS, the PLANE-TREE; a genus of plants belonging to the monoecia class. See BOTANY Index. PLATBAND, in Gardening, a border or bed of flowers, along a wall, on the side of a parterre, frcquently edged with box, &c.

PLATBAND of a door or window, is used for the lintel, where that is made square, or not much marked.

PLATE, a term which denotes a piece of wrought silver, such as the shallow vessel off which meat is eaten. It is likewise used by sportsmen to express the reward given to the best horse at our races.

The winning a plate is not the work of a few days to Sportsthe owner of the horse; but great care and preparationen Die. tionary is to be made for it, if there is any great dependence" on the success. A month is the least time that can be allowed to draw the horse's body clear, and to refine his wind to that degree of perfection that is attainable by art.

st;

It is first necessary to take an exact view of his body, whether he be low or high in flesh; and it is also necessary to consider whether he be dull and heavy, or brisk and lively when abroad. If he appear dull and heavy, and there is reason to suppose it is owing to too hard riding, or, as the jockeys express it, to some grease that has been dissolved in hunting, and has not been removed by scouring, then the proper remedy is half an ounce of diapente given in a pint of good sack; this will at once remove the cause, and revive the creature's spirits. After this, for the first week of the month, he is to be fed with oats, bread, and split beans; giving him sometimes the one and sometimes the other as he likes best and always leaving some in the locker, that he may feed at leisure when he is left alone. When the groom returns at the feeding time, whatever is left of this must be removed, and fresh given; by this means the creature will soon become high-spirited, wanton, and full of play. Every day he must be rode out an airing, and every other day it will be proper to give him a little more exercise; but not so much as to make him sweat too much. The beans and oats in this case are to be put into a bag, and beaten till the hulls are all off, and then winnowed clean; and the bread, instead of being chipped in the common way, is to have the crust clean cut off. If the horse be in good flesh and spirits when taken up for its month's preparation, the diapente must be omitted; and the chief business will be to give him good food, and so much exercise as will keep him in wind, without oversweating him or tiring his spirits. When he takes larger exercises afterwards, towards the end of the month, it will be proper to have some horses in the place to run against him. This will put him upon his mettle, and the beating them will give him spirits. This, however, is to be cautiously observed, that he has not a bloody heat given him for ten days or a fortnight before the plate is to be run for; and that the last heat that is given him the day before the race, must be in his clothes this will make him run with greatly more vigour, when stripped for the race, and feeling the cold wind on every part.

In the second week, the horse should have the same food,