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were kept there by anniversaries of sadness or penance, and sometimes intruded grinning faces through the gloom of the chamber when all the house was asleep. We see that, after all, whether from such causes or from some form of constitutional melancholy, the old man, who walked so briskly and cheerily about the court, and was so sharp and unhesitating in all his notions of what was to be done in secret, carry in him some sense of the burden of life's mystery, and feel the air and the earth to some depth around him to be full of sounds and agencies unfeatured and unimaginable. At any moment they may break through ! The twitter of two robin redbreasts in his room, as he is writing a sermon, sets his heart beating; a curtain rustles— whose hand touched it? Above all, he has a belief in revelation through dreams and coincidences; and as the very definiteness of his scheme of external worship may have been a refuge to him from that total mystery, the skirts of which, and only the skirts, were ever touching him, so in his dreams and small omens he seems to have had, in his daily advocacy of that scheme, some petty sense of near metaphysical aid. Out of his many dreams we are fond of this one: ‘January 5 [1626–7]. Epiphany Eve and Friday, in the night I dreamed,’ he says, “that my mother, long since dead, stood by my bed, and drawing aside the clothes a little, looked pleasantly upon me, and that I was glad to see her with so merry an aspect. She then shewed to me a certain old man, long since deceased, whom, while alive, I both knew and loved. He seemed to lie upon the ground, merry enough, but with a wrinkled countenance. His name was Grove. While I prepared to salute him, I awoke. Were one to adopt what seems to have been Laud's own theory, might not one suppose that this wrinkled old man of his dream, squat on the supernatural ground so near its confines with the natural, was Laud's spiritual genius, and so that what of the supernatural there was in his policy consisted mainly of monitions from Grove of Reading? The question would still remain—at what depth back among the dead Grove was permitted to roam?

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A relative of James Watt, MR JAMES PATRICK MUIRHEAD, M.A., who had access to all the family papers, published a volume in 1854, entitled The Origin and Progress of the Mechanical Inventions of James Watt, three volumes, 1858. The large copperplate engravings of machinery by which it was illustrated, necessarily raised the cost of this work above the means of most people, while the minute descriptions of patents and their relative drawings were more desirable for the use of the scientific engineer and the mechanical philosopher than of the general reader. To meet the wishes of the latter, Mr Muirhead, in 1858, remodelled and reproduced, in a form at once more comprehensive, more convenient, and less costly, the biographical memoir of Watt, incorporating with it the most interesting passages in his correspondence, and, as far as possible, Watt's own clear and forcible descriptions of his inventions. This volume furnishes an interesting account of the career of the great inventor, of whom Sir Walter Scott has said that he was “not only the most profound man of science, the most successful combiner of powers and calculator of numbers, as adapted to practical purposes—was not only one of the most generally well-informed, but one of the best and kindest of human beings.” James Watt was born, on the 19th of January 1736, at Greenock, and came of a family that for more than a hundred years had more or less professed mat'stics and navigation. Many stories are

told of his early turn for science. When he was six years of age, a gentleman, calling on his father, observed the child bending over a marble hearth with a piece of coloured chalk in his hand. “Mr Watt,” said he, “you ought to send that boy to a public school, and not allow him to trifle away his time at home.’ ‘Look how my child is occupied before you condemn him, replied the father. The gentleman then observed that the boy had drawn mathematical lines and circles on the marble hearth, and was then marking in letters and figures the result of some calculation he was carrying on; he put various questions to him, and ended by remarking, “he is no common child. Sitting one evening with his aunt, Mrs Muirhead, at the tea-table, she said: ‘James Watt, I never saw such an idle boy: take a book, or employ yourself usefully. For the last hour, you have not spoken one word, but taken off the lid of that kettle and put it on again, holding now a cup and now a silver spoon over the steam. James was already observing the process of condensation. Before he was fifteen years of age, he had made for himself a small electrical machine with which he sometimes startled his young friends by giving them sudden shocks from it. This must have been only a few years after the Leyden phial was invented. His father's storerooms, in which he kept a stock of telescopes, quadrants, and optical instruments for the supply of ships at Greenock, was a valuable school of observation to the young philosopher, and may have tended to decide the profession which he selected for himself—that of mathematical instrument-maker. At the age of eighteen, he removed to Glasgow to learn this business, and a year afterwards repaired to London for the same purpose. But bad health“a gnawing pain in his back, and weariness all over his body’-obliged him to quit London in the year 1756, and after investing about twenty guineas in tools and useful books on his trade, he returned to Scotland. In 1757 he received permission to occupy an apartment and open a shop within the precincts of the college of Glasgow, and to use the designation of ‘mathematical instrument-maker to the university.’ And now, in his twenty-first year, may be said to have commenced the wonderful career of James Watt as a man of inventive genius. Business was sufficiently prosperous, and in his leisure hours he studied without intermission. ‘Observare' was the motto he adopted, and his object, as he himself expressed it, was ‘to find out the weak side of nature, and to vanquish her;’ ‘for nature, he says again, ‘has a weak side, if we can only find it out. Nothing came amiss. Without knowing one musical note from another, he undertook to build an organ for a mason-lodge in Glasgow. He had studied the philosophical theory of music, and not only did he make the organ, but in the process a thousand things occurred to him which no organbuilder ever dreamed of—nice indicators of the strength of the blast, regulators of it, &c. He afterwards made many organs; and guitars, flutes, and violins of his manufacture are still in existence. About this time he also contrived an ingenious machine for drawing in perspective. The great discovery which led to the ultimate triumphs of the steam-engine was made when Watt was only twentyseven or twenty-eight years of age-namely, in 1764 or 1765. Dr Black, an intimate friend, thus narrates the circumstance:

[The Steam-engine.]

A few years after he was settled at Glasgow, he was employed by the professor of natural philosophy to examine and rectify a small workable model of a steamengine, which was out of order. This turned a part of his thoughts and fertile invention to the nature and improvement of steam-engines, to the perfection of their machinery, and to the different means by which their great consumption of fuel might be diminished. He soon acquired such a reputation for his knowledge on this subject, that he was employed to plan and erect several engines in different places, while at the same time he was frequently making new experiments to lessen the waste of heat from the external surface of the boiler, and from that of the cylinder. But, after he had been thus employed a considerable time, he perceived that by far the greatest waste of heat proceeded from the waste of steam in filling the cylinder with steam. In filling the cylinder with steam, for every stroke of the common engine a great part of the steam is chilled and condensed by the coldness of the cylinder, before this last is heated enough to qualify it for being filled with elastic vapour or perfect steam; he perceived, therefore, that by preventing this waste of steam, an incomparably greater saving of heat and fuel would be attained than by any other contrivance. It was thus in the beginning of the year 1765, that the fortunate thought occurred to him of condensing the steam by cold in a separate vessel or apparatus, between which and the cylinder a communication was to be opened for that purpose every time the steam was to be condensed; while the cylinder itself might be preserved perpetually hot, no cold water or air being ever admitted into its cavity. This capital improvement flashed on his mind at once, and filled him with rapture.

Here was the weak side of nature, by the discovery of which he vanquished her. Dr Robison, also an intimate friend, assigns the discovery to the year 1764. Dr Robison gives an account of an interview with Watt at this time: ‘I came into Mr Watt's parlour without ceremony, and found him sitting before the fire, having lying on his knee a little tin cistern, which he was looking at. I entered into conversation on what we had been speaking of at last meeting—something about steam. All the while Mr Watt kept looking at the fire, and laid down the cistern at the foot of his chair. At last he looked at me, and said briskly: “You need not fash yourself any more about that, man; I have now made an engine that shall not waste a particle of steam. It shall all be boiling hot: ay, and hot water injected, if you please.” So saying, Mr Watt looked with complacency at the little thing at his feet, and, seeing that I observed him, he shoved it away under a table with his foot. I put a question about the nature of his contrivance. He answered me rather drily. I did not press him to a further explanation. * * I found Mr Alexander Brown, a very intimate acquaintance of Mr Watt's, and he immediately accosted me with, “Well, have you seen Jamie Watt?” “Yes.” “He’ll be in high spirits now with his engine, isn't he?” “Yes,” said I, “very fine spirits.” “Ay,” says Mr Brown, “the condenser’s the thing; keep it but cold enough, and you may have a perfect vacuum, whatever be the heat of the cylinder.” The instant he said this, the whole flashed on my mind at once.’

The first experiment was made with a common anatomist's great injection syringe for a cylinder, but the contrivance was perfect in Mr Watt's mind, and fitted the engine at once for the greatest and most powerful, or for the most trifling task. Dr Robison says he is satisfied that when he left town a fortnight before the interview above quoted, Mr Watt had not thought of the method of keeping the cylinder hot, and that when he returned, he had completed it, and confirmed it by experiment.

Sir Walter Scott, according to Mr Lockhart, never considered any amount of literary distinction as entitled to be spoken of in the same breath with mastery in the higher departments of practical life; and if ever a discovery in science was entitled to this exalted position, it was surely that made by James Watt-an invention which is estimated to have added to the available labour of Great Britain alone a power equivalent to that of four hundred millions of men, or more than double the number of males supposed to inhabit the globe. To reap the benefits of his discovery was now the great object to which Watt directed himself, but it was eight or nine years before it turned to the advantage of the public or to the benefit of the inventor. For a time he was associated with an ingenious but unsuccessful man, Dr Roebuck, and neither profited much by the connection. The invention was, however, patented in January 1769, and Watt continued to experiment upon and to perfect the mechanism of his ‘fire-engine. He had married a cousin of his own, Miss Miller, in July 1763, and had now three children; ‘but unhappily,’ says Mr Muirhead, ‘without receiving that triple proportion of corn which, among the Romans, the jus trium liberorum brought with it. Those little voices, “whose crying was a cry for gold,” were not to be stilled by the baser metal of a badly cast Carron cylinder, or the “block-tin and hammered lead” of a Glasgow condenser. We find Watt writing thus: “I am resolved, unless those things I have brought to some perfection reward me for the time and money I have lost on them, if I can resist it, to invent no more. Indeed, I am not near so capable as I once was. I find that I am not the same person I was four years ago, when I invented the fire-engine, and foresaw, even before I made a model, almost every circumstance that has since occurred.’ To carry on the affairs of his household, Watt undertook many occasional commissions. He projected a canal for carrying coals to Glasgow, and received £200 a year for superintending its construction. His mind having been turned to canals, he struck out the idea of the screw-propeller, or ‘spiral oar, as he called it. He made surveys for various canals in Scotland, and among others, by appointment of the Court of Police of Glasgow, the Caledonian Canal, which was afterwards constructed between Inverness and Fort-William. Mr Telford, to whom this great work was principally intrusted, throughout his lengthened labours in connection with it, has borne testimony to the particular correctness and value of Watt's survey. The inventive genius of the man was never still: clocks, micrometers, dividing screws, surveying quadrants, and a hundred other inventions flowed from him with the ease that a littérateur dashes off an article for a magazine. “You might live,” said his friend Dr Small, ‘by inventing only an hour in a week for mathematical instrument-makers.’ In 1773, Mr Watt and Dr Roebuck dissolved their connection, and then began the partnership with Mr Boulton of the Soho Works, in Birmingham, which laid the foundation of Watt's future prosperity. Mr Boulton was possessed of ample means to do justice to the magnitude of Watt's inventions; and the result was, that both realised an ample fortune, and the Soho Works of Birmingham are still among the great establishments of that city. Watt's inventions continued to enrich the world almost until his death, at the patriarchal age of eighty-three. Among the most important of these not mentioned above, were the rotative motion and parallel motion, the throttleva', the steam-gauge, the indicator, the governor, &c.; in connection with the steam-engine, the copyingpress, the steam tilt-hammer, a smoke-consumer, the discovery of the composition of water, &c. These are among the works which we owe to the great inventor and perfecter of the steam-engine. Lord Brougham's beautiful epitaph on Watt, in Westminster Abbey, should never be omitted from any notice of his life and character:

Not to perpetuate a name, Which must endure while the peaceful arts flourish, But to shew That Mankind have learned to honour those Who best deserve their gratitude, The King, His Ministers, and many of the Nobles And Commons of the Realm, Raised this Monument to JAMES WATT, Who, directing the force of an original genius, Early exercised in philosophic research, To the improvement of The Steam-engine, Enlarged the Resources of his Country, Increased the Power of Man, And rose to an eminent place Among the most Illustrious Followers of Science And the real Benefactors of the World. Born at Greenock, MDCCXxxvi.; Died at Heathfield, in Staffordshire, MDccCxix.

The Life of George Stephenson, by SAMUEL SMILEs, 1857, is interesting on account of the history it gives of the application of locomotives to railway travelling; and it is invaluable as affording the example of a great principle triumphing over popular prejudice, ignorance, and the strenuous opposition of ‘vested interests. The railway engineer rose from very small beginnings. He was the son of a labourer in Northumberland, fireman at the pumping-engine of the colliery at Wylam, near Newcastle. George was born in 1781. While a child he ran errands, herded cows, and performed field-labour until, in his fourteenth year, he was promoted to be assistant to his father at the rate of one shilling a day. He could not read, but he imitated everything. He mended clocks and watches, made shoes, and otherwise displayed such ingenuity, that he was appointed engine-wright at Killingworth Colliery at a salary of £100 a year. Here he inspired such confidence in his sagacity and skill, that, on application, he at once obtained permission from Lord Ravensworth, the proprietor, to incur the outlay for constructing what he called a ‘travelling engine’ for the tram-roads between the colliery and the shipping-port nine miles off. With the imperfect tools and unskilled workmen at Killingworth, Stephenson constructed his first locomotive. He called it “My Lord, and at its first trial, on an ascending gradient of 1 in 450, the engine drew eight loaded carriages, of about thirty tons weight, at the rate of four miles an hour. This was on the 25th of July 1814. It was not until 1830 that the public fully recognised the practicability of driving locomotives on smooth rails; and it was then recognised, because the fact could no longer be denied. Stephenson convinced himself of the two great principles—that friction is a constant quantity at all velocities, and that iron is capable of adhesion upon iron without roughness of surface. He therefore discarded cog-wheels on rails and the idea of running locomotives on common roads, and laboured to adapt the locomotive and # rails to the wants of each other, so that, as

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he said himself, they might be like ‘man and wife.’ His success led to his appointment as engineer of the Stockton and Darlington Railway, a line projected in order to find an outlet and new markets for the Bishop Auckland coals. Here he succeeded in establishing the first railway over which passengers and goods were carried by a locomotive. The opening trial took place 27th September 1827, and a local chronicler thus records the event:

[Starting the First Railway Locomotive.]

The signal being given, the engine started off with this immense train of carriages; and such was its velocity, that in some parts the speed was frequently twelve miles an hour; and at that time the number of passengers was counted to be 450, which, together with the coal, merchandise, and carriages, would amount to near ninety tons. The engine with its load arrived at Darlington, a distance of 84 miles, in sixty-five minutes. The six wagons, loaded with coal intended for Darlington, were then left behind, and obtaining a fresh supply of water, and arranging the procession to accommodate a band of music and numerous passengers from Darlington, the engine set off again, and arrived at Stockton in three hours and seven minutes, including stoppages, the distance being nearly twelve miles. By the time the train reached Stockton there were about 600 persons in the train or hanging on to the wagons, which must have gone at a safe and steady pace of from four to six miles an hour from Darlington. ‘The arrival at Stockton, it is added, ‘excited a deep interest and admiration.’

A more important field was, however, necessary, in order to attract public attention, and to test the inherent soundness of the principle propounded by Mr Stephenson. This was found in Liverpool and Manchester. The means of transporting goods between these great cities had not kept pace with the development of the traffic. Cotton, as Mr Huskisson observed in the House of Commons, was detained a fortnight at Liverpool, while the Manchester manufacturers were obliged to suspend their labours; and goods manufactured at Manchester for foreign markets could not be transmitted in time, in consequence of the tardy conveyance. In nine years, the quantity of raw cotton alone sent from the one town to the other had increased by fifty millions pounds weight.

A public meeting was held at Liverpool, and it was resolved to construct a tram-road, an idea which, under George Stephenson, was ultimately extended to a railway suitable for either fixed or locomotive engines. At this time the Bridgewater Canal was yielding a return of the whole original investment about once in two years. The opposition of the proprietors was therefore natural enough, but the scheme was opposed on all sides. In making the survey, Stephenson was refused access to the ground at one point, turned off by the gamekeepers at another, and on one occasion, when a clergyman was violently hostile, he had to slip in and make his survey while divine service was going on. The survey was made, however, in spite of all opposition. The next difficulty was to get leave to make the line. A shower of pamphlets warned the public against the locomotive: it would keep cows from grazing, and hens from laying; the air would be poisoned, and birds fall dead as it passed; the preservation of pheasants and foxes would be impossible; householders would be ruined, horses become extinct, and oats unsaleable; country inns would be ruined; travelling rendered dangerous, for boilers would burst, and passengers be blown to atoms. But there was always this consolation to wind up with—the weight of the locomotive would prevent its moving, and railways could never be worked by steam-power. The bill for the Liverpool and Manchester Railway at length came before a committee of the House of Commons. Privately, Mr Stephenson talked of driving twenty miles an hour; but the counsel warned him of such folly, and in evidence he restricted himself to ten miles an hour. “But assuming this speed,” said a member of the committee, ‘suppose that a cow were to stray upon the line and get in the way of the engine; would not that, think you, be a very awkward circumstance?’ ‘Yes, replied the witness, with his strong Northumberland burr, and a merry twinkle in his eye-‘yes, verry awkward indeed for the coo!’

Mr Stephenson—‘that unprofessional person, as one of the engineers of the day called him—failed to convince the committee, and the bill was lost. “We must persevere, sir, was his invariable reply, when friends hinted that he might be wrong; and a second bill was brought in, which, as the new line carefully avoided the lands of a few short-sighted opponents, passed the House of Commons by 88 to 41, and the House of Lords with the opposition of only Lord Derby and Lord Wilton. The railway was commenced; and though told by the first engineers of the day that no man in his senses would attempt to carry it through Chat Moss, Mr Stephenson did so, at a cost not of £270,000, but of only £28,000, and he completed the line in a substantial and business-like manner. But the adoption of the locomotive was still an open question, and he stood alone among the engineers of the day. The most advanced professional men concurred in recommending fixed engines. ‘We must persevere, sir, was still George's motto. He persuaded the directors to give the locomotive a trial, and he made an engine for the purpose. The trial came on, 6th October 1829. The engine started on its journey, dragging after it about thirteen tons' weight in wagons, and made the first ten trips backwards and forwards along the two miles of road, running the thirty-five miles, including stoppages, in an hour and forty-eight minutes. The second ten trips were in like manner performed in two hours and three minutes. The maximum velocity attained by the ‘Rocket’ during the trial-trip was twenty-nine miles an hour, or about three times the speed that one of the judges of the competition had declared to be the limit of possibility. “Now,' cried one of the directors, lifting up his hands‘now is George Stephenson at last delivered. This decided the question; locomotives were immediately constructed and put upon the line; and the public opening of the work took place on the 15th September 1830.

[Opening of the Liverpool and Manchester Railway.]

The completion of the work was justly regarded as a great national event, and was celebrated accordingly. The Duke of Wellington, then prime-minister, Sir Robert Peel, secretary of state, Mr Huskisson, one of the members for Liverpool, and an earnest supporter of the project from its commencement, were present, together with a large number of distinguished personages. The “Northumbrian’ engine took the lead of the procession, and was followed by the other locomotives and their trains, which accommodated about six hundred persons. Many thousands of spectators cheered them on their way—through the deep ravine of Olive Mount; up the Sutton incline; over the Sankey viaduct, beneath

which a multitude of persons had assembled—carriages filling the narrow lanes, and barges crowding the river. The people gazed with wonder and admiration at the trains which sped along the line, far above their heads, at the rate of twenty-four miles an hour. At Parkside, seventeen miles from Liverpool, the engines stopped to take in water. Here a deplorable accident occurred to one of the most distinguished of the illustrious visitors present, which threw a deep shadow over the subsequent proceedings of the day. The “Northumbrian’ engine, with the carriage containing the Duke of Wellington, was drawn up on one line, in order that the whole of the trains might pass in review before him and his party on the other. Mr Huskisson had, unhappily, alighted from the carriage, and was standing on the opposite road, along which the “Rocket’ engine was observed rapidly coming up. At this moment the Duke of Wellington, between whom and Mr Huskisson some coolness had existed, made a sign of recognition, and held out his hand. A hurried but friendly grasp was given; and before it was loosened, there was a general cry from the bystanders of “Get in, get in '' Flurried and confused, Mr Huskisson endeavoured to get round the open door of the carriage which projected over the opposite rail, but in so doing he was struck down by the “Rocket, and falling with his leg doubled across the rail, the limb was instantly crushed. His first words, on being raised, were, ‘I have met my death, which unhappily proved too true, for he expired that same evening in the neighbouring parsonage of Eccles. It was cited at the time, as a remarkable fact, that the “Northumbrian’ engine conveyed the wounded body of the unfortunate gentleman a distance of about fifteen miles in twenty-five minutes, or at the rate of thirty-six miles an hour. This incredible speed burst upon the world with all the effect of a new and unlooked-for phenomenon.

The fortune of George Stephenson was now made. He became a great man. He was offered, but refused, a knighthood, and his latter days were spent as those of a country gentleman. He died in 1848, at the age of sixty-seven.

[George Stephenson at Sir Robert Peel's seat of Drayton.]

Though mainly an engineer, he was also a daring thinker on many scientific questions; and there was scarcely a subject of speculation, or a department of recondite science, on which he had not employed his faculties in such a way as to have formed large and original views. At Drayton the conversation often turned upon such topics, and Mr Stephenson freely joined in it. On one occasion, an animated discussion took place between himself and Dr Buckland on one of his favourite theories as to the formation of coal. But the result was, that Dr Buckland, a much greater master of tongue-fence than Stephenson, completely silenced him. Next morning before breakfast, when he was walking in the grounds deeply pondering, Sir William Follett came up and asked what he was thinking about? “Why, Sir William, I am thinking over that argument I had with Buckland last night. I know I am right, and that if I had only the command of words which he has, I’d have beaten him.’ “Let me know all about it,' said Sir William, “and I’ll see what I can do for you.’ The two sat down in an arbour, where the astute lawyer made himself thoroughly acquainted with the points of the case; entering into it with all the zeal of an advocate about to plead the dearest interests of his client. After he had mastered the subject, Sir William rose up, rubbing his hands with glee, and said: “Now I am ready for him. Sir Robert Peel was made acquainted with the plot, and adroitly introduced the subject of the controversy after dinner. The result was, that in

the argument which followed, the man of science was 719

overcome by the man of law; and Sir William Follett had at all points the mastery over Dr Buckland. “What do you say, Mr Stephenson?” asked Sir Robert, laughing. “Why, said he, ‘I will only say this, that of all the powers above and under the earth, there seems to me to be no power so great as the gift of the gab. One day at dinner, during the same visit, a scientific lady asked him the question, ‘Mr Stephenson, what do you consider the most powerful force in nature?’ ‘Oh!” said he, in a gallant spirit, “I will soon answer that question: it is the eye of a woman for the man who loves her; for if a woman look with affection on a young man, and he should go to the uttermost ends of the earth, the recollection of that look will bring him back; there is no other force in nature that could do that. One Sunday, when the party had just returned from church, they were standing together on the terrace near the hall, and observed in the distance a railway train flashing along, throwing behind it a long line of white steam. “Now, Buckland, said Mr Stephenson, “I have a poser for you. Can you tell me what is the power that is driving that train?’ ‘Well, said the other, “I suppose it is one of your big engines. “But what drives the engine?’ ‘Oh, very likely a canny Newcastle driver. “What do you say to the light of the sun ?’ ‘How can that be?” asked the doctor. “It is nothing else, said the engineer; “it is light bottled up in the earth for tens of thousands of years—light, absorbed by plants and vegetables, being necessary for the condensation of carbon during the process of their growth, if it be not carbon in another form—and now, after being buried in the earth for long ages in fields of coal, that latent light is again brought forth and liberated, made to work, as in that locomotive, for great human purposes. The idea was certainly a most striking and original one: like a flash of light, it illuminated in an instant an entire field of science.

MR RoBERT STEPHENsoN, son of Mr George Stephenson (born in 1803, and educated partly at the University of Edinburgh), has laboured successfully to bring the railway locomotive to its present perfection. To his genius and perseverance, aided by the practical knowledge of Mr Fairbairn, Manchester, we also owe the principle of the tubular bridge, characterised by Professor Forbes as ‘the greatest discovery in construction in our day. At the Menai Strait, two spaces of 460 feet in width are spanned by these iron tubes. Telford's suspension Menai Bridge—the noblest work of the kind in the kingdom—spans a space of 580 feet.

Other valuable scientific biographies may be here noticed. The Life of Sir Humphry Davy, by his brother, DR JoHN DAVY, has already been mentioned. It accompanies an edition of Sir Humphry's works, nine volumes, 1839–40; and an edition has recently (1858) been made to the memoir by Dr Davy, in a volume of Fragmentary Remains, Literary and Scientific, with a new sketch of the life and selections from the correspondence of Sir Humphry. This work shews us a little more of the interior life of the great chemist, but is unsatisfactory. The Life of Cavendish, by DR GEORGE WILsoN, forms part of the series of publications of the Cavendish Society. The Hon. Henry Cavendish (1731–1810) made important researches in chemistry and electricity. ‘To him we are mainly or entirely indebted for the knowledge of hydrogen as a distinct elastic fluid or gas; of the exact constitution of the atmosphere, and the wonderful constancy of its ingredients; of the composition of nitric acid; and, finally, according to the opinion of most persons—at least till lately—of the non-elementary nature of water and of its precise ingredients.’-(Forbes.) Cavendish was a solitary, incommunicative man, shunn: society, eschewing all the luxuries that

his wealth and rank could have commanded-‘a wonderful piece of intellectual clock-work, says Dr Wilson; ‘and as he lived by rule, he died by it, predicting his death as if it had been the eclipse of some great luminary, and counting the very moment when the shadow of the unseen world should enshroud him in its darkness. Dr Wilson, the biographer of Cavendish, has written treatises on chemistry and electricity, colour blindness, &c. He is a native of Edinburgh (born in 1818), and has been very successful as a chemical lecturer. A Life of Dr John Dalton, by DR HENRY, is another of the valuable publications of the Cavendish Society. Dalton (1766–1844) is the chief author of the theory of chemical equivalents, or the atomic theory—as he preferred to call it—and of many important researches on the constitution of elastic fluids. “Poor, and hardly winning a well-earned subsistence by private tuition, from the time he was himself a child until near the close of his long career—with a few friends, a scanty education, and a scantier library—attaining, through his unaided and almost unheeded efforts, and by means of an apparatus constructed entirely by himself, a position in the world of science unquestionably not second to that of either of his more highly favoured contemporaries, Black or Cavendish.’-(Forbes.) A Life of Dr Black, Professor of Chemistry in the University of Edinburgh (1728–1799), forms one of the best of Lord Brougham's short scientific memoirs. His chemical discoveries are those of latent and specific heat, the former of which was so successfully applied by Watt in his improvement of the steam-engine.

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