at the botanical garden at Paris, I was not surprised to hear that the people in the late revolution respected generally the works of art, and that such things were looked upon really as national property which every man had a common interest in protecting.

This then, such as I have described it, is the state of the rich and poor in England. But what has led to it? -and what will cure or mend it? These are two great questions, which require a great deal of thought, and knowledge, and calmness to answer properly. And he certainly cannot have any one of these qualities who pretends that any single cause has brought about the evil, or that any single remedy can remove it.

I have met with some writings upon this subject which profess to remedy the distresses of the poor in a manner sufficiently summary. According to them the land belongs to every body alike, and as the poor are the most numerous class, it will be perfectly easy for them to seize their due share of it, and they will have a perfect right to do so. Now it is very true that every christian, and indeed every man of common sense and honesty, feels instinctively that this is robbery, and that robbery can never be right. A poor woman gave me, a few weeks since, the best and simplest answer to all such wicked folly: when speaking of her landlord wanting his rent, she said quite naturally that she could not blame him-" for own's own, whether to rich or poor." And whether the writers who preach up these doctrines belong to some of those large gangs of pickpockets and thieves which infest London, and are thus only recommending to others what they are daily practising themselves-or whether they belong to those still more miserable wretches, who not only are doing the devil's service, but confess their master openly, and call themselves after his name-there is no serious fear of such preaching gaining many converts. But yet an honest man, when in great poverty himself, and when seeing others around him in great comfort, may be sometimes sorely troubled and perplexed at the sight, and his understanding may not find so ready an answer as his conscience to a doctrine which his distress renders so tempting. I should be glad therefore to lay the matter, if possible, clearly before the eyes of such men-to explain what the right of property is, and how it is neither just nor expedient to violate it.

It is said that the land belongs to every body. This is the original falsehood of the whole doctrine. Nothing belongs to everybody; but it either belongs to somebody or to nobody at all. The air belongs to nobody-the open sea belongs to nobody, and for this reason-because man has done nothing, and can do nothing, to make them better for his use than God made them from the beginning. The very first day after men were made upon the earth, the sea would carry ships, and the air would supply them with breath, just as perfectly as at this moment. Man has had nothing to do with them but to use them as he found them; and therefore over these God has given him no dominion-they are not his property at all. But with the earth or land, and with all things in it, it is quite different. Men were to subdue the earth—that is, to make it by their labour what it would not have been by itself; and with the labour so bestowed upon it came the right of property in it. Thus every land which is inhabited at all, belongs to somebody-that is, there is either some one person, or family, or tribe, or nation, who have a greater right to it than any one else has: it does not and cannot belong to everybody. But so much does the right of property go along with labour, that civilized nations have never scrupled to take possession of countries inhabited only by tribes of savages-countries which have been hunted over, but never subdued or cultivated. It is true they have often gone further, and have settled themselves in countries which were cultivated, and then it becomes a robbery; but when our fathers went to America and took possession of the mere hunting grounds of the Indians of lands on which man had hitherto bestowed no labour, they only exercised a right which God has inseparably united with industry and knowledge.

But you may say we know that France does not belong to us, nor England to Frenchmen; all that we mean is, that England belongs to every Englishman, and

France to every Frenchman. But all that I want to show is the right of property at all; that is, that some have a greater right to the possession of a thing than others; for if this be once allowed, we need not talk any longer about a state of nature, as it is foolishly called; we have done with beast's nature, and are living according to man's nature-that is, according to LAW and RIGHT, not according to BRUTALITY and MIGHT. It is LAW and RIGHT which say that although France produces wine and oil, and England can produce neither, yet that Englishmen must either get the wine and oil from France with the consent of Frenchmen, or else they must go without them. And it is just the same law and right, which say that although Northumberland has plenty of coal and Kent has none, yet that the men of Kent must either persuade the Northumbrians by fair means to let them have their coal, or they must go without it; or again, which say that although the soil of Bagshot Heath is very poor, and that round about Farnham is very rich, yet that the parishes on Bagshot Heath may not touch the hops of Farnham without the owners' leave; or again, to come down a step lower, it is the self same LAW and RIGHT which will not let the man who has no land eat the corn of his neighbour who has land, unless he can persuade his neighbour, either for love or money, to let him have a share of it.

You may say however further, "we would have the law divide all England equally amongst Englishmen, and surely the law of the land may do what it likes with the land." But the law of the land and the law of property are as old as one another, and one of these cannot upset the other. The holders of property may doubtless make laws about their own property, but those who have none can never make a law about that of others, because the law of property is as old as society itself, and if this be done away with, we go back at once to the state of BRUTES, when every man got what he could, and kept what he could. As men in a savage state may not kill one another, because the right to life is as old as the very existence of man at all; so men in society may not take away property, because the right to hold property is as old as the very existence of society itself.

But are persons without property to starve rather than lay hands on the property of their neighbours? I will ask, in return, what do we think of those dreadful causes in which men in the extremity of famine have even killed one of their number to be food for the rest? We cannot judge of acts of the last dreadful necessity; but we do know that the extremest necessity is no rule for common cases, and that if absolute starvation be allowed to be stronger than the law of property, it does not follow that the same excuse should be allowed to distress and inconvenience. I will not speak of the right of a starving man, or a man with a starving family, to help himself to food if it is denied him, till I shall know that there are found to be any so wicked as to deny it him. But what is to the purpose to speak of, and what, with God's blessing, I hope to speak of, is the wickedness of those who would persuade the poor that poverty, not starvation, may be relieved by robbery; and the equal wickedness of those, who being aware of the poverty of their neighbours, are yet disposed to make no sacrifices to relieve it by means at once rightful and effectual.

SIR RICHARD ARKWRIGHT.

THIS extraordinary man, whose mechanical genius accomplished for the cotton manufacture what Newton did for physics, or Adam Smith for political economy, was born of humble parentage in Preston, Lancashire, on the 23d December 1732. He was the youngest of thirteen children, and did not receive any thing but the most limited education. He was brought up to the trade of a barber; an occupation which could not generate, and, indeed, had rather a tendency to eradicate, an independent spirit (if such did exist), and keep a person in an inferior position in society. But innate force of genius cannot easily be extinguished, but will ultimately vindicate itself, and

raise its possessor to distinction. Such was the case with Richard Arkwright. While he followed this servile trade, he felt that his employment was not a congenial one; and his mind wandered amid thoughts and speculations of another and higher kind. But his means were humble, and he could not easily or suddenly make any marked change in his mode of life. About the year 1760, however (when twenty-eight years of age), he abandoned his orginal employment and its petty cares, though he adopted one not much more dignified. But an active mind, not satisfied with its present bent, is equally relieved and stimulated by a change, though comparatively the new line may not afford the intellect much more scope than the old. In short, he became a dealer in hair. He travelled the country buying the article; and when he had dressed it, sold it in a prepared state to wig-makers. It is said that he discovered a process for dyeing hair, which increased equally his business and his consequence.

But neither of these employments satisfied the active and inventive mind of Arkwright, or could keep his mechanical genius longer dormant. It may safely be predicated that, while he was engaged in these ignoble pursuits, he felt an energy and a noble longing in his breast which could not be satisfied till he discovered the field which nature had meant him to cultivate, and in which he was fitted to achieve distinction.

His first effort in mechanics was an attempt to discover the perpetual motion. Soon discovering the absurdity of this object, he turned his attention to the study of machinery in connexion with the cotton manufacture, a subject which had begun to excite great interest, and in which several inventions had been already made. Meanwhile he formed an acquaintance with John Kay, watchmaker, residing at Warrington, whose services he retained for four or five years; and in connexion with this individual, he devoted his time, from 1767, exclusively to the subject of inventions for spinning cotton. At this time Arkwright's poverty was such, that, being a burgess of Preston, he could not go to the polling booth till the friends of the candidate whom he meant to support presented him with a decent suit of clothes. But, poor though he was, he entertained noble thoughts in his mind, and gilded his humble lot by his ingenious efforts and contrivances. "He was impatient," says Mr Baines, "with whatever interfered with his favourite pursuits; and the fact is too strikingly characteristic not to be mentioned, that he separated from his wife not many years after their marriage, because she, convinced that he would starve his family by scheming when he should have been shaving, broke some of his experimental models of machinery."-(Hist. of Cotton Manufacture, p. 196.) In 1768, his first machine was constructed, and set up in Preston. But apprehensive of meeting with the same hostility which, the year previous, had driven James Hargreaves from that town, he left it, and took up his residence in Nottingham. Here he luckily formed a connexion with a man who could appreciate his invention, namely, Mr Jedediah Strutt of Derby, the celebrated improver and inventor of the stocking-frame, and who then was in partnership with Mr Need of Nottingham, as stocking manufacturers. In 1769, Arkwright obtained his first patent for spinning by rollers; and Messrs Need and Strutt became his partners in the manufacturing concerns which it was proposed to carry on under it. Before this great invention, carding and spinning were executed in cottages by the hand. Now, both processes were effected by machinery. Previously, calico was made of cotton and linen; the warp being linen, the weft cotton. The reason was, that, till Arkwright's machine was invented, it was found impossible by any means then known to spin the fibres of cotton into a thread sufficiently strong to be used as warp.

The first mill erected for spinning cotton by this method was at Nottingham, and was worked by horse power; but, in 1771, another mill was built at Cromford, Derbyshire, to which motion was given by water; and hence the machine was called the water-frame, and the thread water-twist. In both these miils Arkwright had an interest as a partner of Messrs Need and Strutt.

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This may be regarded as the commencement of what is called "The Factory System" in England.

The two inventions, of the spinning-jenny by Hargreaves (whose biography we gave in our last Number), and of the water-frame by Arkwright, broke down the barrier which had previously obstructed the advance of the cotton manufacture. The water-frame spun a hard and firm thread fitted for warps; and from this time the warps of linen-yarn was abandoned, and goods were, for the first time, woven wholly of cotton. The jenny was peculiarly adapted for spinning weft, so that the two machines, instead of coming in conflict, were brought into use together.

Arkwright followed up his great invention by various improvements and combinations of machinery, and took out a second patent in 1778. He also took out a patent for carding, and for the crank and comb. But his patents were pirated, particularly his water-frame; and so extensively were his privileges invaded, that he raised actions against no fewer than nine manufacturers. But having failed in the first of them, on the ground that the specification or description of the invention was not sufficiently minute and full, he abandoned the others. Four years afterwards (namely, in 1785), having raised another action, and led evidence as to the efficiency of his specification, he was reinstated in the possession of his monopoly. But the manufacturers again combined against him, and succeeded by a writ of scire facias to get his patent altogether cancelled! He applied for a new trial, but was refused by the court. Meanwhile he had published what is called his "Case," calling on the legislature to afford him protection; but this appeal had no effect, and Arkwright received no public reward or public support, but was left unaided to fight his own battles.

The conduct of the rival cotton manufacturers towards Arkwright was sufficiently selfish and malicious; but it was not confined to invading his monopoly. They formed a combination not to purchase his yarn, and thus to effect, so far as they could, the ruin of an ingenious and meritorious man. In consequence of this, a considerable stock of yarn lay on his hands. But ingenuity and merit are not easily put down. They possess in themselves the elements of permanence and success. Arkwright and his partners were themselves driven to undertake the manufacture of their own yarns. They first made them into stockings, and afterwards into calicoes, such as are made at the present time. The opposition, indeed, on the part of the rival manufacturers was so great, that Arkwright states in his "Case," that "it was not till upwards of five years had elapsed after obtaining his first patent, and more than L.12,000 had been expended in machinery and buildings, that any profit accrued to himself and partners."

But though the commencement of his manufacturing career was inauspicious, he ultimately overcame all the selfish opposition which was directed against him. He enlarged his works at Cromford. He formed other establishments; and even extended his speculations to Scotland, founding, along with Mr Dale, the New Lanark mills, in which he was a partner for several years. He was now rapidly making a large fortune, not merely by his several manufactories, but by the sale of his patent machines, and of licenses to use them. He granted this permission on condition of receiving a certain sum for each spindle. His partnership with Mr Strutt terminated about 1783; but he retained the works at Cromford, which are still carried on by his family.

In 1786, he was appointed High Sheriff of Derbyshire; and having presented an address of congratulation from that county to the King on his escape from the attempt of Margaret Nicolson on his life, he received the honour of knighthood: and certainly never was such honour more deserved or more appropriate.

The most marked traits in the character of Arkwright, from his earliest years, was his wonderful ardour and perseverance. His plans, too, were all laid with skill as well as prosecuted with energy; and amid all his ingenuity, he possessed the utmost tact, judgment, and discretion. During the later years of his life, in particular, he laboured in his multifarious concerns from

five o'clock in the morning till nine at night; and when considerably more than fifty years of age, feeling that the defects of his education placed him under great difficulty in conducting his correspondence and in the general management of his business, he encroached on his sleep in order to gain an hour each day to learn English grammar, and another hour to improve his writing and orthography! He was a severe economist of time; and, that he might not waste a moment, he generally travelled with four horses, and at a very rapid speed. His concerns in Derbyshire, Lancashire, and Scotland, were so extensive and numerous, as to show at once his astonishing power of transacting business, and his allgrasping spirit. So unbounded was his confidence in the success of his machinery, and in the national wealth to be produced by it, that he would make light of discussions on taxation, and say that he would pay the national debt. His speculative schemes, in short, were vast and daring. He contemplated entering into the most extensive mercantile transactions, and buying up all the cotton in the world, in order to realize an enormous profit by the monopoly.

But this unremitting attention to business, and the mental excitement which he necessarily underwent, were not favourable to health. Besides, his constitution had never been entirely sound. From his early years he had been afflicted with severe asthma; and this complaint, with a complication of other disorders, accelerated, if not produced, by the extent of his business connexions, brought him to a comparatively early grave on the 3d of August 1792, before he had completed his sixtieth year, leaving behind him a fortune of half a million sterling, and works equally extensive and profitable. Considering the deficiencies of his early education, and the whole circumstances of his life, Sir Richard Arkwright may be justly regarded as an extraordinary man; and certainly the unrivalled manufacturing eminence of England is more indebted to him than to any other individual. His genius and successful enterprise have thrown a lustre over his name and family. One of his sons recently died, reckoned to be the wealthiest commoner in the empire; and another of his descendants has a seat in the House of Commons as member for Leominster. No human being of proper feeling will grudge or envy the distinction to which any descendant of Richard Arkwright can attain; but, on the contrary, will regard that name as one of the proudest of which the country can boast.*

THE IMPORTANCE OF CHEMISTRY. BARON LIEBIG has recently published two volumes of deep interest, called "Familiar Letters on Chemistry," the English editions of which have been edited by Dr Gardner. We have no fault to find with the translations, except the price, which excludes them from the people-a circumstance all the more to be regretted, as they are not likely to be found in circulating libraries. The follow

"Richard Arkwright, it would seem, was not a beautiful man; no romance hero with haughty eyes, Apollo lip, and gesture like the herald Mercury; a plain, almost gross, bag-cheeked, pot-bellied Lancashire man, with an air of painful reflection, yet also of copious free digestion, a man stationed by the community to shave certain dusty beards in the northern parts of England at a

halfpenny each. To such end, we say, by forethought, oversight, accident, and arrangement, had Richard Arkwright been, by the community of England and his own consent, set apart. Neverthe. less, in strapping of razors and lathering of dusty beards, and the contradictions and confusions attendant thereon, the man had notions in that rough head of his; spindles, shuttles, wheels, and contrivances plying ideally within the same; rather hopeless-looking; which, however, he did at last bring to bear. Not without difficulty! His townsfolk rose in mob around him for threatening to shorten labour, to shorten wages; so that he had to fly with broken washpots, scattered household, and seek refuge elsewhere. Nay, his wife, too, as I learn, rebelled; burnt his wooden model of his spinning wheel; resolute that he should stick to the razors rather; for which, however, he decisively, as thou wilt rejoice to understand, packed her out of doors. Oh! reader, what an historical phenomenon is that bag-cheeked, pot-bellied, much-enduring, and much inventing barber! French revolutions were a-brewing; to resist the same in any measure, imperial kaisers were impotent without the cotton and cloth of England; and it was this man that had to give England the power of cotton. '--Thomas Carlyle.

ing passages from one of the letters will most likely be new to many of our readers.

"We have only to look around us to perceive at once that the science to which we are devoted,Chemistry,-has by no means been favoured, in an equal degree, with other sciences, such as botany, mineralogy, geology, or geography; that hitherto no adequate encouragement has been extended to it, no sacrifices made to ensure its advancement, no efforts commensurate with its importance to extend its cultivation, and to make it an essential element in popular education. Herein lies a great disparity between chemistry and other sciences. It is not, however, difficult to discover the causes of this comparative neglect of chemistry. The literary man and the statesman have not been impressed, in the course of their early studies, with the principles indispensable to the successful study of nature. Chemistry was long known only as it was subservient to the physician for the preparation of his purgatives and his emetics. Whilst it was thus engrafted on the medical sciences it could obtain no independent position. The physician was but slenderly furnished with chemical truths, and yet the science had no existence except for him and the apothecary. When, however, those who framed the systems and guided the practice of education, saw the great advantages which agriculture, arts, and manufactures might derive from chemistry and natural philosophy, they admitted these sciences to a certain rank, and bestowed on them a certain measure of attention. From being merely an instrument of the physician, chemistry then became one of the main levers of commercial industry. The measures adopted to ensure this extended application of the science, however, were imperfect, and inadequate to the purpose. But chemistry is susceptible of being made subservient to far higher offices; it may be employed as a means of cultivating the mind, of training the human faculties for the universal investigation of nature. In this point of view it has not been contemplated. Many well-informed people still regard chemistry as the art of making experiments according to certain rules, very useful in the manfacture of soda and soap, in fixing good and permanent colours upon silk and cotton fabrics; but as an investigation of nature, or as an universal guide to its study, it is to most persons altogether unknown.

"It is so congenial to the human mind to inquire into the causes of the natural phenomena existing around us, and presented to us in the daily changes taking place in all visible objects, that those sciences which gave satisfactory explanations and correct answers to our inquiries, exercise more influence on the advancement of mental cultivation than any other. Thus the relations of light to the earth, the succession of day and night, the variation of the seasons, and the differences in the temperature of different climates, gave birth to astronomy. As the mind advances in knowledge, as it becomes enlightened by the influx of truths, no matter from what source, its capabilities are increased, its powers strengthened and elevated, and its progress in all other directions proportionately facilitated. When we obtain a correct knowledge of the link which connects certain associated phenomena, when we have made an acquisition of a new truth relative to causation, it becomes equivalent to a merable phenomena which had previously escaped our new and additional sense, enabling us to perceive innunotice, and which still remain mysterious or altogether invisible to others.

"In the progressive growth of astronomy the other physical sciences were developed, and when these had been, to a certain degree, successfully cultivated, they gave birth to the science of chemistry. And now we may anticipate that ORGANIC CHEMISTRY will perfect our knowledge of the laws of life-the science of physiology.

"But it must not be forgotten that our predecessors determined the duration of the year, explained the changes of the seasons, and calculated eclipses of the moon, without any acquaintance with the laws of gravitation; that people have built mills and constructed pumps without knowing anything of atmospheric pres

sure; that glass and porcelain were manufactured, stuffs dyed, and metals separated from their ores by mere empirical processes of art, and without the guidance of correct scientific principles. Even geometry had its foundation laid in experiments and observations; most of its theorems had been seen in practical examples, before the science was established by abstract reasoning. Thus, that the square of the hypothenuse of a rightangled triangle is equal to the sum of the squares of the other two sides, was an experimental discovery, or why did the discoverer sacrifice a hecatomb when he made out its proof?

"How different now is the aspect of the discoveries of the naturalist, since the spiritual impetus of a true philosophy urges him to investigate phenomena in order to understand their causes and laws, whether in natural philosophy, chemistry, or in other sciences. From one sublime genius-from NEWTON-more light has proceeded than the labour of a thousand years preceding had been able to produce. The true theory of the movements of the heavenly bodies, the law which regulates the fall of bodies, i. e. gravitation, has become the parent of innumerable other discoveries. Navigation, and, in consequence, commerce and industry immediately felt its influence, and every individual of our species has derived, and will continue to derive, as long as mankind exists, incalculable benefits therefrom, both intellectual and material.

"Without an acquaintance with the history of physics it is impossible to form any correct opinion of the effect which the study of nature has exercised upon the cultivation of the mind. In our schools mere children are now taught truths, the attainment of which has cost immense labour and indescribable efforts. They smile when we tell them that an Italian philosopher wrote an elaborate treatise to prove that the snow found upon Mount Etna consists of the same substance as the snow upon the Alps of Switzerland, and that he related proof upon proof that both these snows, when melted, yielded water possessed of the same properties. And yet this conclusion was really not so very palpable, since the temperature of the two climates so widely differ, and no one in those days had any notion of the diffusion of heat over the surface of the earth. When a schoolboy takes a glassful of liquid, and placing a loose piece of paper over it, inverts the glass without spilling a drop of the contents, he only astonishes another child by his performance, and yet this is the identical experiment which renders the name of Torricelli immortal. It is a variation of that experiment with which the burgomaster of Magdeburgh (Otto von Guerike) threw the emperor and the princes of the empire at Ratisbon into speechless astonishment. Our children have more correct notions of nature and natural phenomena than had Plato! they may treat with ridicule the errors which Pliny has committed in his Natural History!

"By the study of history, of philosophy, and of the classics, we obtain a knowledge of the intellectual world, the laws of thought, of mental inquiry, and of the spiritual nature of man. Whilst we hold communion with the spirits of the great and good of all ages, we derive from the experience of past centuries the power of soothing and governing the passions, and of softening the heart; we are enabled to comprehend man as he exists at the present time, since his moral nature remains ever the same. We are taught to embellish, and present, in the most engaging form, the principles of truth, of right, and of religion, and thus to make the most enduring impression upon the minds of others. History and philosophy, however, could not prevent men from being burnt for witchcraft. For when the great Kepler went to Tubingen to save his mother from the stake, he succeeded only by proving that she possessed none of the characteristic signs

is, as is well known, an apparently very simple theory of the phenomena of combustion. We have now experienced the great benefits and blessings which have sprung and been diffused from this view. Since the discovery of oxygen the civilised world has undergone a revolution in manners and customs. The knowledge of the composition of the atmosphere, of the solid crust of the earth, and of water, and their influence upon the life of plants and animals, was linked with that discovery. The successful pursuit of innumerable trades and manufactures, the profitable separation of metals from their ores, also stand in the closest connexion therewith. It may well be said that the material wealth of empires has increased many-fold since the time oxygen became known, and the fortunes of individuals have been augmented in proportion. Every discovery in chemistry has a tendency to bring forth similar fruits. Every application of its laws is capable of producing advantages to the state in some way or other, augmenting its powers, or promoting its welfare.

"In many respects chemistry is analogous to mathematics. On the one hand, the application of this latter science enables us to measure land, to erect buildings, and to raise weights, and, as in arithmetic, becomes an instrument, the skilful employment of which secures most obvious and universal advantages; on the other hand, mathematics enable us to draw correct logical conclusions according to definite rules, teach us a peculiar language, which allows us to express a series of such conclusions in the most simple manner, by lines and symbols intelligible to every one who understands this language: give us the power to deduce truths by means of certain operations with these lines and symbols; and furnish us with an insight into relations of things formerly obscure or unknown to us. The mechanician, the natural philosopher, the astronomer, employ mathematics as an indispensable instrument for the attainment of their ends. They must, indeed, be so practised in its management that its application becomes a mechanical habit, requiring only the exercise of memory. But it is not the mere instrument which plans and executes the work, but the human intellect. You will admit that without the power of observation, without judgment, without sagacity, all mathematical knowledge is useless. You may imagine a man who, favoured by a good memory, has rendered himself intimately acquainted with every theorem of mathematics, who has obtained an eminent degree of skilfulness in handling this instrument, but who is altogether unable to invent a problem for solution. If you propose to him a problem, and give him the conditions for the solution of a question, he will succeed in obtaining an answer by performing the current operations with which he is familiar, and express it in a formula consisting of certain symbols, the meaning of which, however, is perfectly unintelligible to him, because he is deficient in other attainments essential for judging of its truth. Such a man is a mere calculating machine. But as soon as he possesses the capacity and the talent of proposing a question to himself, and testing the truth of his calculations by experiment, he becomes qualified to investigate nature. For from whence should he derive his problems if not from nature? He is denominated a mechanician, an astronomer, or a natural philosopher, if starting from observation, he is able to ascertain the connexion of certain phenomena and the causes producing them; and then is capable, not merely of expressing the results in a formula, in the language of the mathematician, but of making an application thereof, exhibiting his formula in the shape of a phenomenon or external fact, thereby testing its truth. The astronomer, the mechanician, the natural philsopher, therefore, in addition to mathematics, which they use only as an instrument, still require the art of observing and interpreting phenomena, the ability to present the results of abstract reasoning in a visible shape by means of a machine or some form of apparatus ; in fact, to prove the correctness of their conclusions by experiment. The natural philosopher proposes to himself the solution of a problem-he endeavours to ascertain the causes of a given phenomenon, the variations it undergoes, and the conditions under which these changes