thought of; but the supposed impossibility of getting across the elevated central region which has been called the Backbone of England, had hitherto prevented any attempt to execute it. This was, however, precisely such an obstacle as Brindley delighted to cope with; and he at once overcame it, by carrying a tunnel through Harecastle Hill, of 2880 yards in length, at a depth, in some places, of more than 200 feet below the surface of the earth. This was only one of five tunnels excavated in different parts of the canal, which extended to the length of ninety-three miles, having seventy-six locks,* and passing in its course over many aqueducts. Brindley, however, did not live to see the whole of this great work executed, which was finished by his brother-inlaw, Mr. Henshall, in 1777, about eleven years after its commencement.

During the time that these operations, so new in this country, were in progress, the curious crowded to witness them from all quarters, and the grandeur of many of Brindley's plans seems to have made a deep impression upon even his unscientific visitors. A letter which appeared in the newspapers, while he was engaged with the Trent and Mersey Canal, gives us a lively picture of the astonishment with which the 'multitude viewed what he was about. The writer, it will be observed, alludes particularly to the Harecastle Tunnel, the chief difficulty in excavating which arose from the nature of the soil it had to be cut through. "Gentlemen come to view our eighth wonder of the world, the subterranean navigation which is cutting by the great Mr. Brindley, who handles rocks as easily as you would plum-pies, and makes the four elements subservient to his will. He is as plain a looking man as one of the boors of the Peak, or one of his own carters; but when he speaks, all ears listen, and every mind is filled with wonder at the things he pronounces to be practicable. He has cut a mile through bogs, which he binds up, embanking them with stones, which he gets out of other parts of the navigation, besides about a quarter of a mile into the hill Yelden, on the side of which he has a pump, which is worked by water, and a stove, the fire of which sucks through a pipe the damps that would annoy the men who are cutting towards the centre of the hill. The clay he cuts out serves for brick to arch the subterranean part, which we heartily wish to see finished to Wilden Ferry, when we shall be able to send coals and pots to London, and to different parts of the globe."

* The use of locks in the construction of canals through a district of various levels has been explained, pp. 91, 92.

H

It would occupy too much of our space to detail, however rapidly, the history of the other undertakings of this description to which Mr. Brindley's life was actively devoted. The success with which the Duke of Bridgewater's enterprising plans for the improvement of his property were rewarded, speedily prompted numerous other speculations of a similar description; and many canals were formed in different parts of the kingdom, in the execution or planning of almost all of which Brindley's services were employed. He himself had become quite an enthusiast in his new profession, as a little anecdote that has been often told of him may serve to show. Having been called on one occasion to give his evidence touching some professional point before a Committee of the House of Commons, he expressed himself, in the course of his examination, with so much contempt of rivers as a means of internal navigation, that an honourable member was tempted to ask him for what purpose he conceived rivers to have been created: when Brindley, after hesitating a moment, replied, "To feed canals." His success as a builder of aqueducts would appear to have inspired him with almost as fervid a zeal in favour of bridges as of canals, if it be true, as has been asserted, that one of his favourite schemes contemplated the joining of Great Britain to Ireland by a bridge of boats extending from Portpatrick to Donaghadee. This report, however, is alleged to be without foundation by the late Earl of Bridgewater, in a curious work which he published some years ago at Paris, on the subject of his predecessor's celebrated canal.

Brindley's multiplied labours and intense application rapidly wasted his strength, and shortened his life. He died at Turnhurst, in Staffordshire, on the 27th of September, 1772, in the fifty-sixth year of his age, having suffered for some years under a hectic fever, which he had never been able to get rid of. In his case, as in that of other active spirits, the soul seems to have

"O'er-informed its tenement of clay;"

although the actual bodily fatigue to which his many engagements subjected him must doubtless have contributed to wear him out.

No man ever lived more for his pursuit, or less for himself, than Brindley. He had no sources of enjoyment, or even of thought, except in his profession. It is related, that having once, when in London, been prevailed upon to go to the theatre, the unusual excitement so confused and agitated him as actually

to unfit him for business for several days, on which account he never could be induced to repeat his visit. His total want of education, and ignorance of literature, left his genius without any other field in which to exercise itself and spend its strength than that which the pursuit of his profession afforded it. But its power, even here, would probably not have been impaired if it could have better sought relaxation in variety; on the contrary, its spring would most likely have been all the stronger for being occasionally unbent. As we have already mentioned, he was all but entirely ignorant of reading and writing. He knew something of figures, but did not avail himself much of their assistance in performing the calculations which were frequently necessary in the prosecution of his mechanical designs. On these occasions his habit was to work the question by a method of his own, chiefly in his head, only setting down the results at particular stages of the operation; yet his conclusions were generally correct. His vigour of conception, in regard to machinery, was so great, that, however complicated might be the machine he had to execute, he never, except sometimes to satisfy his employers, made any drawing or model of it; but, having once fixed its different parts in his mind, would construct it without any difficulty, merely from the idea of which he had thus possessed himself. When much perplexed with any problem he had to solve, his practice was to take to bed, in order to study it; and he would sometimes remain, we are told, for two or three days thus fixed in meditation to his pillow.-From Craik's 'Pursuit of Knowledge under Difficulties.'

JAMES WATT.

As the locomotive engine rushes on its way through the open country, stopping at towns and villages, taking with it passengers and merchandise, we seldom think of him by whom the wonderful piece of mechanism, which seems like a thing gifted with intelligence, was brought almost to perfection. That man was James Watt, a native of Greenock in Scotland, where he was born in January, 1736. Watt, it must be noticed, was the improver, not the inventor of the steam-engine. From his earliest days to the end of his life he suffered from bad health, which

interrupted very much his attendance at school. When he was eighteen years old he was sent to London, and there apprenticed to a maker of mathematical instruments, but the state of his health obliged him to return in less than a year to his native land. In 1757, however, he settled at Glasgow, where he was appointed mathematical instrument maker to the University. In 1763 he ceased to reside in his rooms in the College, and removed to a house in the city, entering then upon the business of an engineer. Soon afterwards the Professor of Natural Philosophy in the University sent to Watt a small model of Newcomen's engine to be repaired, and it was this little model which led him to turn his attention again (as he had done some time previously) to the subject of steam as a power to move wheelcarriages.

To understand what James Watt did to improve the steamengine it is necessary to know the chief parts of this piece of mechanism and how they act. The reader can imagine a strong cylinder, or tube, or barrel, in which there is a closely fitting piston, which is forced upwards and downwards by the expansive power of steam, which is admitted into the cylinder above and below the piston from a boiler. It is plain that motion being thus obtained, and the strokes of the piston up and down being well regulated, the end of the piston-rod can be attached to any piece of work that is to be done; in fact, that the power of the engine can be directed to any point where it is wanted. The first difficulty which Watt attacked was that of producing in the lower part of the cylinder a vacuum,* so that the piston might come downwards easily without meeting any resistance from steam and air. Now all the means which Newcomen and Savery had adopted for producing the vacuum previous to the downward stroke of the piston were imperfect. For example, Savery's plan of throwing cold water on the outside of the cylinder to condense the steam in it, not only cooled the steam which was to be got rid of, but also the cylinder, which had to be again made hot, and this could be done only by a wasteful use of fuel. Watt began to think about the subject; he saw all the difficulties of it, and anxiously sought for a simple plan of conquering them. At last a very simple idea occurred to him. He thought he would provide a separate vessel in which to condense the steam, and this vessel he would connect with the cylinder by a pipe. He believed that if he kept this separate vessel-which he called the "condenser "-in contact with cold water, the steam which had * A vacant or unfilled space.

rushed into it from the cylinder through the pipe would become condensed; a partial vacuum would thus be produced in the 66 condenser," to fill which more and more steam would rush in from the cylinder until the cylinder itself would become though still hot and dry- quite empty, and then the piston would easily descend. This was a simple plan, and when Watt tried it he found it to act as he had supposed it would. So much for what he did as regards the lower part of the cylinder below the piston. He found that air descended with the piston, got between it and the sides of the cylinder, however closely fitting the piston might be, and thus tended to cool the cylinder in its lower part. So to get rid of this drawback, he opened communications above the piston as he had done below it, namely, between the condenser and the boiler. He made an air-tight chamber at the top of the cylinder with a hole in it, just large enough to admit the rod of the piston, and the rod—to make it air-tight—was covered with hemp. It was contrived, in fact, that when there was a vacuum at one end of the cylinder, there should always be steam at the other end to force the piston either up or down. Another of Watt's simple contrivances was called the Governor, which lessened the quantity of steam when it was acting too forcibly, and increased it when it did not act forcibly enough.

Watt was rewarded by the admiration and respect of several public bodies, and died in 1819 at the ripe age of eighty-four. We have great reason to feel grateful to James Watt for what he did to improve the steam-engine, which not only on railways, but when fixed in mills, factories, arsenals, printing-offices, foundries, &c., is a means of increasing the wealth, the comfort, and even the intelligence of the whole world of human beings.-John Flint.

CAPTAIN JAMES COOK.

COLUMBUS himself, one of the greatest men that ever lived, if it be a grand idea grandly realized that constitutes greatness, not only, while leading the life of a seaman, pursued assiduously the studies more particularly relating to his profession, rendering himself the most accomplished geographer and astronomer of his time, but kept up that acquaintance which he had begun at school with the different branches of elegant literature. We are