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of the purity or fitness for respiration of air generally. This paper obtained for him the Copleian medal, in presenting which to him, Sir John Pringle, the president of the Royal Society, said, I present you, sir, with this medal, the palm and laurel of this community, as a faithful and unfading testimonial of their regard, and of the just sense they have of your merit, and of the persevering industry with which you have promoted the views, and thereby the honour, of this society; and, in their behalf, I must earnestly request you to continue your liberal and valuable inquiries, whether by farther prosecuting this subject, probably not yet exhausted, or by investigating the nature of some other of the subtile fluids of the universe. These, sir, are, indeed, large demands; but the Royal Society have hitherto been fortunate in their pneumatic researches; and were it otherwise, they have much to hope from men of your talents and applications, and whose past labours have been crowned with so much success."

After Priestley had been engaged for six years in his ministry at Leeds, he accepted an offer made to him by Lord Shelburne (afterwards Marquess of Lansdowne), to reside with him in the nominal capacity of librarian, but, in reality, as a literary companion to his lordship. The offer was made in so handsome a manner, and upon such advantageous terms, to one whose family was fast increasing, that Priestley at once accepted it; and removed, in consequence, to a house at Calne, in Wiltshire, near his lordship's seat. His connexion with this nobleman lasted for seven years; during which, he not only continued his investigations of the subject of his former researches, but greatly distinguished himself as a metaphysical and polemical writer. As the works which he wrote in this character, probably led to his separation from Lord Shelburne, we shall, in this place, enumerate some of them. 1775, he published, preparatory to his purpose of introducing to public notice the Hartleian theory of the human mind, his Examination of the Doctrines of Common Sense, as held by the three Scotch writers, Drs. Reid, Beattie, and Oswald. His edition of Hartley shortly afterwards appeared, in his preface to

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which he expressed some doubts of the immateriality of the sentient principle in man. He had previously, it should be observed, declared himself a believer in the doctrine of philosophical necessity. Opinions so favourable to infidelity, brought upon him much obloquy; but, regardless of all consequences in the pursuit of truth, he pushed his inquiries more closely and assiduously than ever. These investigations terminated in his entire conversion to the material hypothesis, or that of the homogeneity of man's nature, and led to his publication, in 1777, of Disquisitions on Matter and Spirit, in which he gave a history of the doctrines concerning the soul, and openly supported the ideas he had adopted. It was followed by A Defence of Unitarianism, or the simple Humanity of Christ, in opposition to his Pre-existence, and of The Doctrine of Necessity.

The publication of these works was followed by a manifest coolness on the part of Lord Shelburne towards the subject of our memoir, but whether in consequence of the odium which the author incurred by them, or of the sentiments which they contained, is doubtful. To all appearance, however, the parties separated on amicable terms, and the public heard of nothing to the contrary; but yet, when, as Priestley informs us, he came to London, and proposed to call on the noble lord, the latter declined his visits. He also tells us, that during his connexion with his lordship, he never once aided him in his political views, nor ever wrote a political paragraph. Lord Shelburne he admits, treated him in every respect as he could wish; left him under no restraint with respect to his pursuits; and occasionally took him with him in his excursions, one of which, in 1774, was a tour to the continent. The manners and society of a nobleman's house were not, however, quite congenial to one, whose tastes were simple, and whose address was plain and unceremonious; yet, it must be confessed, that posterity is somewhat indebted to Lord Shelburne, for having afforded to Priestley opportunities of pursuing his scientific researches, which he could not have enjoyed as a dissenting minister. He allowed, also, Priestley to

suits. Various theological works canie, in succession, from his pen, and, in particular, his History of the Corrup tions of Christians, and History of Early Opinions concerning Jesus Christ. They gave rise, as he had anticipated, to much controversy, into which he entered, without reluctance, and in the course of which he displayed neither anger nor spleen. When the dissenters renewed their application to parliament for the repeal of the test and corporation acts, he resorted to his pen in their behalf; and at the same time took the opportunity of declaring his hos

retain an annuity of £150, which was honourably paid to the last; and, it is said, that when the bond for securing to him this sum was burnt at the riots of Birmingham, his lordship presented him, in the handsomest manner, with another. It may not, perhaps, be uninteresting to mention, that whilst Priestley was in Paris, with his noble patron, the celebrated infidel philosophers and politicians to whom he was introduced, told him, that he was the first person they had met with, of whose understanding they had any opinion, who was a believer in Christianity. Upon interrogating them closely, how-tility to all ecclesiastical establishments, ever, he found that none of them had any knowledge either of the nature or principles of the Christian religion!

In 1774-7, Dr. Priestley published, in succession, three volumes, entitled Experiments and Observations on dif ferent kinds of Air, which were afterwards extended, by him, to six octavo volumes. The important matter which they contained, has rendered the name of the author familiar in all the enlightened countries of Europe; and their publication formed an era in that knowledge of aëriform fluids, which is the basis of modern chemical science. His other works, relating to chemistry, are too numerous to mention; and we shall therefore proceed with a detail of that part of his life in which he figured as a theologian and politician.

On leaving Lord Shelburne, Dr. Priestley removed to Birmingham, on account of the advantages he might derive there from able workmen, in pursuing his experimental inquiries. The defalcation of his income was supplied by a subscription among some noble and generous friends, which he, without hesitation, accepted; considering it as more honourable to himself than a pension from the crown, which, it is said, might have been obtained for him, if he had desired it, during the brief administration of the Marquess of Rockingham, and the early part of that of Mr. Pitt. His stay at Birmingham had not been long, when he was unanimously appointed to the charge of the principal dissenting congregation in that town. He entered into the duties of his office with his accustomed zeal, performing them all without interrupting his philosophical and literary pur

which he regarded as inimical to the rights of private judgment, the propagation of truth, and the spirit of Christianity. He predicted their downfal in his publications on the subject, which at length caused him to be considered as the most dangerous and inveterate enemy of the established church in its connexion with the state. The clergy of Birmingham were amongst the foremost in opposing the claims, so ably advocated by him in behalf of the dissenters, and displayed not a little irritation in repelling his attack upon their own rights. Priestley answered them in a series of familiar letters to the inhabitants of Birmingham, which added still more to the anger of his opponents, in consequence, no less, of the ironical style in which they were written, than of the matter which they contained. In this state of things, the party feeling that prevailed upon the subject received additional excitement from the circumstances of the French revolution; an event with respect to which people were yet most oppositely and powerfully influenced. The anniversary of the capture of the Bastile on the 14th of July, had been kept as a festival, by the friends of the cause, and its celebration was announced to take place, at Birmingham, in 1791. The subject of our memoir declined attending the meeting, but in the riots which ensued, the populace marked him out as the object of their fury. They set fire to his house, from which he narrowly escaped with life, and destroyed his fine library, manuscripts, and apparatus, amidst the most brutal exultations. It was some time before he could reach a place of safety, being

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tracked in his flight with all the ardour of a blood-hound, and hunted like a proclaimed criminal. In aggravation of the circumstances of this outrage, which was attended with the conflagration of many other houses and places of worship, it appears, upon undoubted authority, that it was rather favoured than controlled by some, whose duty ought to have led them to active interference for the preservation of the public peace. That they did not do so, however, is less surprising, than that party fury should have been specially directed against one, who had made himself so conspicuous a champion on the opposite side, and who had directed | his attacks without any regard to the dictates of caution or worldly policy. His appeal to government for indemnification from the loss which he had sustained, was not altogether in vain; though the compensation awarded him fell far short of what he had a right, in justice, to expect. He bore his calamity with great resignation, and had the satisfaction to witness the exertions of many to support him under it, who admired his virtue and talents, and regarded him as a sufferer for his principles. Removing to Hackney, he was shortly afterwards chosen to succeed Dr. Price, as minister to the dissenting congregation of that place ; and, at the same time, connected himself with the new dissenting college lately established there. Here, resuming his usual occupations, he passed some time in ease and serenity; no man, as it has been said of him, being ever blessed with a mind more disposed to view every event on the favourable side, or less clouded by care and anxiety. But the malignity of party dissension had not yet subsided, and public prejudice continuing to operate still strongly against him, he found himself and his family so much molested, that he, at length, determined to quit a country so hostile to his person and principles.

He chose America for the place of his retreat, and accordingly embarked for that country in the month of April, 1794. On his arrival, he took up his residence at the town of Northumberland, in Pennsylvania, where his first care was to get together a well-furnished library and chemical laboratory. This he effected, but not without great

labour and difficulty, in consequence of the remote situation of his place of abode. He was soon after offered, but thought fit to decline, a chemical professorship in Philadelphia; but he was by no means idle at home. He pursued with ardour his philosophical experiments; but theology, which was always his favourite study, was the subject nearest his heart, and his sense of its importance increased with his years. He was not altogether free from the effects of political animosity, even in America, being regarded, by the government, with suspicion and dislike during the administration of Mr. Adams. Under that of Mr. Jefferson, however, he was treated in a friendly manner, and he survived all disquiet on that head. The greatest trials of his fortitude in the latter part of his life were his domestic calamities, which he bore in a manner worthy of his temper and his principles. Those which he most acutely felt were the death of his youngest son, a very promising young man, and afterwards of his truly estimable wife. He was himself suffering from a debility of his digestive organs, which at length brought on such a state of bodily weakness, as made it manifest he had not long to live. Of this, his disease gave decided warnings, in | January, 1804, and the effect upon him was to cause him to lose no time in finishing the literary tasks in which he was engaged, and particularly in preparing for the press some works in which he was greatly interested. Among these were, a continuation of his Church History, and Notes on all the Books in the Bible, which, he learned with great satisfaction, that his friends in England had raised a subscription to enable him to print, without any risk to himself. Like a man setting his affairs in order, previously to a long journey, he is represented to have continued, to the last hour of his life, giving, with the utmost calmness and self-collection, directions relative to his posthumous publications intermixed with discourses expressive of the fullest confidence in those cheering and animating views of a future existence, that the Christian faith opened to its disciples. He died on the 6th of February, 1804, so quietly, that those who sat beside him did not perceive the last moment of his existence.

Aware, possibly, that the solemn period was at hand, and unwilling to shock his children, who were sitting by his bed-side, by his departure, he had taken the precaution of putting his hand before his face.

Dr. Priestley is to be considered in the quadruple character of a philosopher, theologian, metaphysician, and politician. Of his philosophical writings, those containing his Observations on Air are the most important, though not so popular as his History of Electricity. This, however, Dr. Thompson, in his Annals of Philosophy, gives good reasons for not thinking deserving of the great reputation which it acquired for its author. The chief merit he awards to it, is that of collecting, in one view, the scattered facts which were spread through a great variety of preceding books, and which, at that time, it was difficult to obtain. Dr. Priestley's two principal discoveries in electricity were, that charcoal is a perfect conductor of electricity; and that all metals may, without exception, be oxydized, by passing through them a sufficiently strong electrical charge. He made no additions nor improvements to the theory of electricity; whilst so many have taken place since his history appeared, that his work in no degree represents the present state of that science. His History of the Discoveries relative to Light and Colours, has added nothing to his reputation; his deficiency in mathematical knowledge unfitted him for such a work, and his treatise on the subject, had he not distinguished himself in other departments, would scarcely have brought him into notice. Of his Elementary Treatise on Electricity and Natural Philosophy, and his book on perspective, it will suffice to say, that they are written in a very lively and entertaining manner, and well calculated for enticing young men to their respective studies.

We now come to consider his discoveries in pneumatic chemistry, of which, however, it will be incompatible with the design of this work to give anything but a general outline. The first of his great discoveries was nitrous gas, the properties of which he ascertained with great sagacity, and almost immediately applied it to the analysis of air. Its assistance was most material

in all subsequent investigations, and it, in a great measure, led the way to our present knowledge of the constitution of the atmosphere. His next grand discovery was oxygen gas, which was accounted as one of the most important revolutions in chemistry. This substance, however, is said to have been previously discovered by Scheele; and Lavoisier likewise laid claim to it; but the French philosopher was undoubtedly preceded by Priestley, who showed Lavoisier the method of procuring it during the year 1774, a considerable time before his pretended discovery was made. We are likewise indebted to Dr. Priestley for the discovery of most of the other gaseous bodies at present known, and for the investigation of their properties. Among these may be mentioned sulphuric acid, fluoric acid, muriatic acid, ammoniacal, carbureted hydrogen, carbonic oxide, and nitrous oxide. It was he who first discovered the acid produced when the electric spark is taken for some time in common air; a fact which led afterwards to the knowledge of the constituents of nitric acid, which contributed so essentially to the establishment of the new chemical doctrine. To him also we are indebted for a

knowledge of the great decrease of bulk which takes place when electric sparks are passed through ammoniacal gas; to say nothing of his curious experiments on the freezing of water; on the amelioration of atmospherical air, by the vegetation of plants; on the oxygen gas given out by them in the sun; and on the respiration of animals. "To enumerate, indeed," as Mr. Kirwan says, " Dr. Priestley's discoveries, would be to enter into a detail of most of those that have been made within the last fifteen years. How many invisible fluids, whose existence evaded the sagacity of foregoing ages, has he made known to us? The very air we breathe he has taught us to analyze, to examine, to improve: a substance so little known, that even the precise effect of respiration was an enigma, until he explained it. He first made known to us the proper food of vegetables, and in what the difference between them and animal substances consisted. To him pharmacy is indebted for the method of making artificial mineral waters, as well as for a shorter method of preparing

other medicines; metallurgy, for more powerful and cheap solvents; and chemistry, for such a variety of discoveries as it would be tedious to recite-discoveries which have new modelled that science, and drawn to it, and to this country, the attention of all Europe. It is certain, that, since the year 1773, the eyes and regards of all the learned bodies in Europe have been directed to this country by his means. In every philosophical treatise his name is to be found; and in almost every page they all own that most of their discoveries are due either to the repetition of his discoveries, or to the hints scattered through his works." This is, undoubtedly, true; for Lavoisier availed himself of all the discoveries of Priestley, repeated and arranged them, and, by means of them chiefly, and of the discoveries of Mr. Cavendish, succeeded in establishing his peculiar opinions. Priestley, it should be added in this place, continued, till the end of his life, an advocate for the phlogistic theory; and, the year before his death, published a curious paper, in which he summed up all his objections to the Lavoiserian theory.

As a theologian, Dr. Priestley may rank among the most zealous opponents of atheism, as well as of trinitarian Christianity. He considered Moses and Jesus Christ as divine instructors, endowed with the power of working miracles, in order to prove the truth of their mission, and who each inculcated the system of morality best suited to the particular times in which they lived. He denies the sacred historians to have been inspired; but considers, upon the whole, the evidence for their fidelity and veracity to be so strong, that it would be a greater miracle to admit the possibility of their accounts being forgeries, than to admit the truth of the Christian religion. Christ, he considers, as a mere man, and, in consequence, denies the immaculate conception, together with the doctrine of the atonement, of election, and reprobation, and of the eternity of a future punishment. He believed in the existence of a God, infinite in wisdom, power and goodness, and considered the system of the universe, the best possible; the apparent imperfections and the evil which exists in it

being necessary to produce the greatest possible quantity of happiness. These opinions he proposed and defended in various publications, written for the most part hastily, and marked rather by force and acuteness, than by accuracy or profundity. His conversion to Unitarianism is one of the proudest boasts of its followers; but though no man could be more sincere in his conversion, he has not left the grounds of the adoption of this system less disputable, or more generally convincing than before.

As a metaphysician, he is chiefly distinguished as the strenuous advocate of Dr. Hartley's theory of association, upon which he founded the doctrine of materialism and of necessity as legitimate inferences. Dr. Aikin, and other of his biographers, give him credit for treating these abstruse subjects with great perspicuity and acuteness, qualities which characterize the chief portion of his writings. We join not the cry which they raised against him, but cannot forbear deprecating the manner in which he has treated Dr. Reid, in his Examination of the Doctrine of Common Sense as held by Dr. Reid, Oswald, and Beattie. He has there commented upon the writings of the former in a tone quite at variance with his usual moderation, and by no means proper towards one who was, beyond all doubt, a better mathematician and metaphysician, and whose doctrines, on the above subject, he is generally allowed to have failed in his attempts to overthrow.

His political principles were similar to those afterwards advocated by Godwin; he was an advocate for the perfectibility of the human species, or, at least, its continually increasing tendency to improvement. In his Essay on the First Principles of Civil Government, he lays it down as the foundation of his reasoning, that it must be understood, whether it be expressed or not, that all people live in society for their mutual advantage; so that the good and happiness of the members,—that is, the majority of the members of any state, is the great standard by which everything relating to that state must be finally determined; and though it may be supposed that a body of people may be

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