nexion alone, will be found to extend to above one thousand four hundred miles.

The oldest canal in the northern part of the kingdom is that between the Forth and Clyde, which was executed by the celebrated Smeaton, although its plan was revised by Brindley. It commences at Grangemouth, on the Carron, at a short distance from where that river falls into the Forth, and originally terminated at Port Dundas, in the neighbourhood of Glasgow. A portion of this canal, owing to the great descent of the ground over which it passes towards the west, has no fewer than twenty locks in the first ten miles and a half. It was afterwards carried farther west to Dalmuir, on the Clyde; and is now connected with the Glasgow and Saltcoats canal, whose course is across the counties of Renfrew and Ayr, to the river Garnock, which flows into the Atlantic opposite to the Isle of Arran. More recently, a branch has been extended from its north-eastern extremity, along the south bank of the Forth, as far as Edinburgh; so that the whole now forms an uninterrupted line of canal navigation from the east to the west coast of Scotland. The famous Caledonian Canal, in the north of Scotland, also unites the two opposite seas, and indeed runs pretty nearly parallel to a part of the line that has just been described. It was commenced in 1802, under the management of Mr. Telford, who conducted it throughout; and was first opened on the 23d of October, 1822. The distance between the German and the Atlantic Oceans, measured in the direction of this canal, is two hundred and fifty miles; but of this nearly two hundred and thirty miles, consisting of friths and lakes, were already navigable. The canal itself, therefore, which has cost about a million of pounds

sterling, is only, properly speaking, about twenty miles in length; and, had not steam navigation been fortunately discovered while the work was going on, there seems every reason to believe that the cut would have been nearly useless.

The entire length of the canal navigation already formed in Great Britain and Ireland is not much under three thousand miles. The whole of this is the creation of the last seventy years, during which period, therefore, considerably above forty miles of canal may be said to have been produced every year, a truly extraordinary evidence of the spirit and resources of a country, which has been able to continue so large an expenditure, for so long a time, on a single object; and which has in a single year, during that period, spent almost as much money upon war as all those canals together have cost for three quarters of a century. If Brindley had never lived, we should undoubtedly ere now have been in possession of much of this accommodation; for the time was ripe for its introduction, and an increasing commerce, every where seeking vent, could not have failed, ere long, to have struck out for itself, to a certain extent, these new facilities. But had it not been for the example set by his adventurous genius, the progress of artificial navigation among us would probably have been timid and slow, compared to what it has been. For a long time, in all likelihood, our only canals would have been a few small ones, cut in the more level parts of the country, like that substituted in 1755 for the Sankey Brook, the benefit of each of which would have been extremely insignificant, and confined to a very narrow neighbourhood. He did, in the very infancy of the art, what has not yet been outdone; struggling, indeed, with such difficulties, and triumphing over them, as could be scarcely exceeded by any his suc

man, the celebrated JOHN HARRISON, who, in 1767, obtained the parliamentary reward of twenty thousand pounds for the invention of his admirable timepiece for ascertaining the longitude at sea, may be quoted as another example of self-taught genius, but not so entirely unaided by books. He was born at Pontefract, in Yorkshire, in 1693, and was bred a carpenter; yet he very early manifested a taste for mathematical science, which is said to have been first awakened by a manuscript copy of some lectures of Saunderson (the blind mathematician), that accidentally fell into his hands; and it should seem that he was not so entirely without education as to be unable to peruse and profit by them. Before he was twenty-one, he had made two wooden clocks by himself, and without having received any instructions in the art. We have, in a former chapter, mentioned the circumstance of his having been first induced to think of applying himself to the construction of marine chronometers by living for some time in sight of the sea. It was in 1728 that he first came up to London, in order to prosecute this object; but he had to devote to it the anxious labours of nearly forty years before his inventions were perfected, or their general merit fully recognized. The art of watchmaking owes several valuable improvements to Harrison; among which may be particularly mentioned the gridiron pendulum, and the expansion balance-wheel-the one serving to equalize the movements of a clock, and the other those of a watch, under all changes of temperature-and both depending upon the unequal stretching under change of temperature of two different metals, which are so employed to form the rod of the pendulum and the circumference of the wheel, that the contraction of the one exactly counterbalances the expansion of the other. Although, however, a most skilful and inge

nious artist, Harrison never acquired any acquaintance with literature; and a little work, which he published in his old age, in explanation of some of his ideas on the construction of time-pieces, is miserably ill-written. He died in London, in 1776, at the age of eighty-three.

Of these, and all such instances, it may safely be remarked that, far from proving the inutility of scientific acquirements, they only show how far, in one particular line, natural genius can carry its possessors without cultivation; and make us regret their having wanted those helps which, even in that line, would have carried them so much farther.

CHAPTER XX.

Knowledge of Languages. Magliabecchi; Hill; Wild; Aram; Purver; Pendrell.

Ir mechanical invention does not necessarily imply much study of books, and may seem, on that account, a province of intellectual exertion fitted for persons who have not enjoyed the advantages of a regular education, as being one in which natural sagacity and ingenuity, as much as literary attainments, are requisite to ensure advancement, the same thing can hardly be said of another department, in which selftaught genius has frequently made extraordinary progress; we mean the study of languages.

This

is the sort of knowledge, indeed, which, in common parlance, is more peculiarly called learning. Its acquisition, in the circumstances alluded to, can only be the result of a love for, and familiarity with, books, and of what we may call the literary habit thoroughly formed.

There are three purposes for which languages may be studied, independently of their gratifying that general desire of information which makes both the acquirement and the possession of all knowledge delightful. One use, and an infinitely important one, to be made of the knowledge of languages, is the study of that intellectual mechanism by which they have been formed, and of which they present us, as it were, with the impress or picture. Another department of philosophy to which this knowledge is a key, is that relating to the early his