matter remains where it did; and the inquirer, after wandering in a labyrinth of erudition, is left to form his conclusion by balancing the value of opposite conjectures. Knight, for one hundred guineas; and so pleased was that gentleman with the acquisition and the terms, that he presented to Dr. Clarke a piece of plate, fashioned in the form of a handsome cream-jug, after the model of an antique vase, with a classical inscription. not out of idle curiosity, but purposely to enlarge the sphere of knowledge. While this discussion engaged the attention of Dr. Clarke, his prolific mind was employed also upon a subject, of a nature as remote as possible About this time appeared, from the from the antiquarian dispute. In the university press, a volume descriptive very midst of the controversy, he wrote of the "Marbles which Dr. Clarke had an elementary treatise on mineralogy; brought from the Euxine, Archipelago, but though the work was actually and Mediterranean, and deposited in printed, it was never published. About the Vestibule of the public Library.' the same time he was appointed se- His object in publishing this book was nior tutor of his college; and in De- not vain-glory, but to stimulate others cember, 1805, he was ordained by his to similar exertions. And the wish old friend Dr. Beadon, bishop of Bath was gratified; for numerous additions and Wells. Another change was now were soon made to the classical founabout to take place; and on the 25th dation which Dr.Clarke and Mr.Cripps of March in the following year, he was had laid in the university by their nomarried by the same prelate to Miss ble presents: and so effective was the Angelica Rush, the daughter of Sir example which they set, that several William Rush, baronet, of Wimble- students of fortune undertook expedon. Upon this occasion, the noble-ditions to Greece, Turkey, and Egypt, men and fellow commoners of Jesus College presented Dr. Clarke with a piece of plate, accompanied by a letter, expressive of their obligations to him as a tutor, and their regret at the loss which the society would sustain by his removal. At the time of his marriage, the college living of Harlton fell vacant, to which he was presented, and thus had an opportunity of continuing his residence at Cambridge, the distance of that place from the vicarage being no more than seven miles, so that he was enabled to discharge the duty himself, which he did without a curate. Three years after, he was presented to the rectory of Yeldham, in Essex, which was tenable with Harlton. At the beginning of 1807, he received permission from the heads of the university to deliver a course of lectures on mineralogy; and the year following a grace passed the senate for the foundation of a new professorship in his name. This performance of Dr. Clarke was soon followed by the first volume of his Travels, the publication of which took place at the commencement of the year 1810, and the rest came out successively; but of the sixth, only twelve chapters were finished by him at his death, the rest being supplied by his friend Mr. Walpole. Of the first volume, three quarto editions were printed; but of the latter ones, only two. There was, however, an octavo impression of the first four volumes; and translations of the whole have appeared in different languages. For the first five volumes, the author received the sum of £5845, and for the last, the booksellers paid to the family £750. It is superfluous to dilate in praise of a work which is paramount as a standard of authority on the countries described: instead, therefore, of culogizing what all the world admires, we Dr. Clarke now endeavoured to dis-shall quote lord Byron's letter to the pose of the literary curiosities which he had brought from the East, and accordingly a negotiation was begun with the curators of the Bodleian Library at Oxford, the university of Cambridge not having funds for the purpose. After a short delay, the bargain was concluded for the entire collection, at the sum of one thousand pounds. The Greek coins were soon afterwards sold to Mr. Richard Payne author, in 1812: "Will you accept my very sincere congratulations on your second volume, wherein I have retraced some of my old paths, adorned by you so beautifully, that they afford me double delight. How much you have traversed! I must resume my seven-leagued boots, and journey to Palestine, which your description mortifies me not to have seen more than ever. I still sigh for the Egean. Shall not you always love its bluest of all waves, and brightest of all skies? You have awakened all the gipsy in me. I long to be restless again, and wandering: see what mischief you do, you won't allow gentlemen to settle quietly at home. I will not wish you success and fame, for you have both, but all the happiness which even these cannot always give." Meanwhile, the reputation of Dr. Clarke as a mineralogist became widely diffused, and his lectures were in consequence numerously attended. He was also invited to deliver a course at the Royal Institution; but, by the advice of his friends, who thought that his time was already sufficiently occupied, he declined accepting the flattering proposal. But though, in this instance, he yielded to the counsel of others, there was another subject on which he strenuously resisted every repression, in order to obey the impulse of what he conceived to be in the highest degree obligatory. In December, 1811, a meeting was called at Cambridge, for the establishment of a Branch Bible Society, and Dr. Clarke entered so warmly into the concern, that he engaged to second the proposed measure. This rather alarmed some of his timid friends, who were apprehensive that in so doing he might injure his worldly interests; for at this time an extraordinary fear prevailed, both in and out of the university, that the indiscriminate circulation of the scriptures endangered the church. Dr. Clarke therefore was desired to keep away from the meeting; but he had made up his mind, and no consideration could induce him to break his promise. The place of assembly was the town-hall, which, at the time appointed, was crowded to excess. The earl of Hardwicke took the chair, and the effect produced cannot be better expressed than in the words of Dr. Clarke to a correspondent: "Could I now but describe the grandeur and solemnity of this meeting! The most surprising and overwhelming sight to me was, that the faces of that vast assembly, even of the young gownsmen, were seen streaming with tears of rapture. Of course, this was not neglected by one of our speakers, whom you may guess, and who, with almost inspired energy, called it "a contribution, every drop whereof was treasured in the phials of heaven!"-Well, lord Francis Osborne moved the resolutions, and I rose (God help me, thinks I) to second them. It is impossible to describe the animating shouts with which I was encouraged-every sentence was cheered. M. said, the effect was such, he expected they should have all their windows broken. Letters with gratulations have poured in upon me from every quarter.' " Soon afterwards he employed his pen in the same cause, and composed a pamphlet in defence of the Bible Society, upon general principles, against professor, now bishop, Marsh. Besides this, Dr. Clarke took an active part in the formation of several local institutions having the same object; and wherever he came, he contributed, by his spirit and eloquence, to conquer all prejudices against the cause, and to render it popular. In 1818 he had a narrow escape for his life. Having been accustomed to make experiments upon minerals with the common blow-pipe, the thought occurred to him of heightening the power of the instrument, by adding to it the agency of the hydrogen and oxygen gases. After many trials, he succeeded in constructing a machine for this purpose, to which he gave the name of the Gas Blow-Pipe. On communicating the same to Dr. Wollaston, he was dissuaded from the use of it, as it might prove dangerous by explosion. Notwithstanding this caution, he went on, and submitted a number of obstinate substances to the action of his blow-pipe, till at last the prediction was fulfilled; and Dr. Clarke himself, with two gentlemen and a servant, very nearly fell victims to their curiosity, by the bursting of the copper reservoir, and the destruction of the walls. Of this accident he thus wrote to a friend: “I sacrificed the whole month of August to chemistry. Oh! how I did work! It was delightful play to me; and stuck to it day and night. having blown off both my eyebrows and eye-lashes, and nearly blown out both my eyes, I ended with a bang that shook all the houses round my lecture room." This mishap did not relax his ardour, though it made him more cautious; and he went on improving and guarding the machine till he was enabled by it to accomplish At last, all that he wanted; and in 1819 he collected his observations into an octavo volume, entitled "The Gas Blow-Pipe, with Engravings, &c." While thus engaged, he was elected Librarian of the University of Cambridge; and in such estimation was he held, that all those who had intentions to become candidates for the office, gave up their pretensions on being informed that the professor of mineralogy was a competitor. About the same time, Dr. Clarke received another mark of distinction, which gratified him exceedingly. The citizens of Glasgow having subscribed a large sum for a statue in honour of their countryman, sir John Moore, selected the doctor to compose the inscription. From the several performances which he sent them, the committee selected a short one, partly Greek and partly English, and transmitted the author fifty guineas for the purchase of a piece of plate. In 1820, a Philosophical Society was formed at Cambridge, of which the professor was one of the first and most active members, as his papers in the transactions evince. He was also associated with several other literary and scientific institutions, to whom he made many valuable communications. It is pleasing also to record, that in the midst of these various labours and engagements, the duties of his office as a christian minister were not neglected. He was a frequent preacher before the University; besides which, after his removal to Cambridge from Harlton, he undertook the cure of the parish of All Saints. But all these exertions combined to shake a constitution which to appearance gave the promise of longevity. the doctor was constantly employed, night and day, in going from one bed to another. Though they all recovered, it was very slowly, and Mrs. Clarke continued ill nearly the whole of the winter, when, to increase the distress, the affectionate husband and tender father was seized with a nervous disorder, which ultimately terminated in an affection of the brain, that carried him off on Saturday the 9th of March 1822; and on the 18th of the same month his remains were interred in the chapel of Jesus College, where his academical friends have subscribed to erect a monument to his memory. Few such men as Dr. Clarke arise in an age. His ardour for knowledge, and patience of fatigue; the versatility of his genius, and the vigour of his judgment-appear sufficiently in the sketch that we have given of his active, varied, and useful life. But one part of his character, we must here notice in the words of his most intimate friend and biographer, Mr. Otter. As a parish priest, he was kind, charitable, and attentive; not contenting himself with his prescribed duties on a Sunday, but visiting his flock frequently in the week, as occasion required, and otherwise employing himself in devising means for their spiritual welfare and improvement. Among these may be mentioned a Sunday-school, which he established and conducted himself with unusual attention and success, catechizing the children from the reading desk, and making them repeat their lessons in the presence of the congregation, whom he thus contrived to interest in their progress. It is almost needless to add, that, as a preacher, he was popular and In the summer of 1821 he was afflict-eminent, for, endowed as he was with ed with dizziness, and weakness of sight, which terminated in a polypus of the nose. For this last it was necessary to undergo an operation, which was successfully performed in London by sir Astley Cooper; and the patient felt such relief, that he returned to Cambridge invigorated in health and spirits. Soon after his arrival, however, another calamity befell him, which suspended all his pursuits, and overwhelmed him with grief. Mrs Clarke, who was far advanced in pregnancy, and three of the children, were attacked with a typhus fever, during which trying visitation so many requisites for eloquence, and capable of animating the tamest and most ordinary subjects, it would have been strange indeed if he could have been any thing but powerful and energetic when engaged in topics involving the deepest interests of humanity, and inspired by a book, which, independent of its doctrines and precepts, was always regarded by him with the utmost admiration and reverence. But it is pleasing to record, that the effect of his discourses from the pulpit was even more striking and persuasive than his fine qualities might have given reason to expect; and the crowded audiences, both of young and old, that always attended him at St. Mary's, afford the best proof of the estimation in which he was held by the University. A prospect is held out, which we hope to see speedily realized, that some of his sermons will be given to the public. ANALYSIS OF GEOLOGY. (Continued from col. 814.) THE next subject to be considered is chlorine. This name was given by that great chemist sir Humphrey Davy, to a gas, which had up to that period been deemed a compound, when he discovered it to be a simple substance; the name arises out of its colour, which is a greenish-yellow. Chlorine is found combined with hydrogen in muriatic acid gas, and cnters into the composition of common-salt. became partially light, are through the medium of this gas. The high degree in which hydrogen is inflammable renders it a dangerous neighbour to the miner; the flame of whose candle frequently occasions explosions of this gas in the mines, which lamentably overwhelm multitudes of those highly useful members of society with destruction. Hydrogen is left in its gaseous state by the decomposition of water in subterranean currents, lakes, &c. when, amidst the play of affinities, the oxygen of the water forsakes the hydrogen, and converts metals or other minerals into oxides; which is perpetually the case in all internal as well as external waters: for every oxide formed in water must decompose as much water as the oxygen which formed the water sustained. Hydrogen being, therefore, set at liberty by this unabating tendency in oxygen to forsake it for other substances, accumulates in confined caverns, in mines, in wells, and indeed in every situation where a free current of air is not ad Iodine is found combined with soda, &c. in sea-weeds, and is generally extracted from the incinerated product of these weeds, known by the commer-mitted to divide and dissipate the cial name, kelp. The discovery of iodine, as a simple substance is novel. In its solid form iodine resembles the metals, and in its gaseous state it acts similarly to oxygen and chlorine upon other substances. Fluorine, the supposed radical of the fluoric acid, is found in a fusible spar common in the county of Derby and elsewhere, which has the general name of Derbyshire spar; and also in other minerals combined with lime, &c. This acid acts upon glass; which renders it exceedingly useful in the arts, the fine arts especially, for the purpose of etching on glass, &c. Hydrogen is found combined with oxygen in water; hence its name, the water-former. It is also a component part of our atmosphere, and of the air in mines, wells, and caverns of the earth, &c. Hydrogen likewise occurs combined with various substances in the mineral world. This gas is the lightest of all ponderable matter; it is therefore used to inflate balloons, in order to their ascent into the higher regions of the air. Hydrogen is the gas which supplies the power of burning with flame to every substance used by man, for the economical production of light and heat; thus all the artificial means whereby the dark periods of the revolutions of our sphere mass. The great coal fields, from the peculiar construction of the strata therein, and the vast and numerous escarpments which there mount into the atmosphere and condense the vapours in the middle regions of the air, present great internal currents of water; these coal fields also contain abundance of minerals upon which oxygen acts with peculiar freedom, especially iron, in the shape of ore, pyrites, &c. thus great accumulations of liberated hydrogen pervade these whole regions, and distress the coal miners to a degree beyond all others. Hydrogen in these mines becoming mingled, and in some cases combined with carbon, which abounds in coal, by increasing the quantity of mephitic gas, increases the danger. Quicklime in the act of slaking emits a steam, part of which is the vapour of the water suddenly heated up by the latent heat of the lime, and the remainder is an impalpable powder of lime, these rising to the roof of the mine, where mephitic gas abounds, have been found to neutralize that gas in a certain degree. Alcohol, or, which is much cheaper, acetic acid, in the crude form in which it is procured from wood, treated with dry heat in iron cylinders for the calico printers, or indeed other acids evaporated, in the confined parts of coal mines, from numbers of earthen vessels, by the heat of hot irons placed beneath them, I have found exceedingly useful in neutralizing the foul air of mines, especially when charged in the evening, and the hot irons renewed in the night. One boy would cause to be heated, and distribute, hot irons beneath the vessels which contain the alcohol or acid to be evaporated, sufficient for a mine which would employ twenty miners. Oxygen, when assisted by heat, has been known to unite in part with carbon, and also with hydrogen; and it is worth such an effort as the preceding, yea, one much more expensive, to neutralize, if only partially, the mephitic gas in extensive mines; if even one explosion annually was prevented thereby, some scores, nay, hundreds of valuable lives would be saved, which now fall incessant sacrifices to the terrific explosions which take place in coal mines; the details of which in the public prints harrow up the soul; to say nothing of the immense damage done by these explosions to the mines themselves. district into death. How ought we to live-we who live in the very gates of death, and are in a state of probation for eternity? Carbon is found native, and perfectly pure, in the diamond; it is also found combined with lime, magnesia, oxygen, &c. in limestone. In the various strata of coal, called pit-coal, carbon is combined with asphalt, maltha, bitumen, sulphur, alumina, silica, iron, oxygen, hydrogen, &c.; and in these strata, as well as in vegetables, it is abundant. The incinerated product of vegetables is charcoal, (in which carbon abounds,) when wood is exposed to heat in a close vessel or pit, in order to prevent this gas from being dissipated. Carbon is, therefore, abundant within and upon this sphere, and from a fixed and solid form, as in the diamond, to a subtile and invisible gas, floating in and forming a component part of our atmosphere, occupies every grade which the mineral and vegetable worlds afford. Carbon is also of considerable use. This gas seems to be the bond which fixes in the form of rocks and strata the numerous masses of lime which occupy so large a portion of the crust of this sphere; for no sooner is carbon sublimed from limestone, than lime becomes a powder or earth: it probably acts in the same capacity in the strata of coal, and perhaps in vegetables. Naturally or artificially incorporated with iron, carbon imparts qualities to that metal of great value in the arts. Iron is itself abundantly useful, more abundantly so, indeed, than any other metal; but were it not for those peculiar properties iron possesses in union with carbon, in the form of steel, a blank would remain in the arts, which iron itself, and indeed nothing but immense circumlocutory labour and ingenuity beyond all calculation, could fill up; if even all these would suffice. Azote, or nitrogen, is found combined with oxygen, carbon, hydrogen, &c. Nitrogen constitutes so large a proportion as four-fifths of the whole matter of the atmosphere, in those regions which are contiguous to the earth. Exposed to this gas, when pure, flame is extinguished, and animal life terminated; notwithstanding, it cannot be discerned by the organs of either taste or smell in animals. Well was it said by one of old, "In the midst of life we are in death." To use parables, four-fifths of the very air we breathe is death; the odds are frightfully against us-four to one. What a miracle is life! It seems to be by extracting the fifth portion, in the act of breathing, from the mass of death, that life is continued. The Infinite holds the issues of life and Boron occurs combined with suldeath in his hands; and how multi- phur, magnesia, iron, lime, soda, watudinous are the agents which sub-ter, &c. in crystals, in incrustations, serve his providences, and deal these in detached masses, and also in a state out to man! A pestilence, walking in of subterranean solution, boiling up darkness, surrounds us incessantly; in the springs of Persia and Thibet. this we draw into our very vitals at From these countries, South America, every breath, and from this pestilence &c. it is generally brought to Europe, we extract its oxygen, and live. A in an impure state, in small pieces mere decomposition of the atmosphe- like gum, bearing the commercial ric air in any one district would pre- name, tincal. After purification, first cipitate the millions which inhabit that by moist, and secondly by dry heat, |