the other hand, a railway formed with the view of carrying out a rapid movement, and taking loads of goods in hourly succession, must have every engineering part of the line adapted to the working of it. Thus, the radius of a curve which in one case might be admissible, in the other would be dangerous, and must be enlarged, or dispensed with entirely in the one case steep gradients would be of little consequence, in the other exceedingly injurious; while a curve placed at the base of an incline in the latter would be still more mischievous and absurd. For heavy traffic and great velocity the excavations and embankments must, therefore, be proportionate in width the viaducts in strength the bridges and tunnels in elevation and width-road-crossings avoided and while the gradients are adapted for such increase of speed, the strength and stability of the rails must bear a corresponding proportion.

Too often, perhaps, from overlooking these preliminary points, have railways been constructed ill adapted for the rate of speed, and weight, and number of the trains worked on them. Had the present quick rate of speed been foreseen, might not the steep inclines on the Liverpool and Manchester railway (at Whiston, 1 foot in 96, and at

Sutton, 1 in 89) have been avoided, which, in spite of all the advantages of the increase of the motive power, form permanent impediments to rapid transit? And, in a similar manner, would not the curves of short radii which exist on many lines have been avoided?

ments

In the construction of railways, the cuttings and excavations that is, the formation of the line of way through elevations, and their perforation, where requisite, with tunnels—the filling up of deep ravines, or the forming of embankare all points that evince the talent and skill, and test the experience, of the engineer. As the main object is to bring the line of way as near to a level as possible, by the judicious planning of the line many thousands of pounds may be saved. Engineering in these days has assumed a new feature from bygone times. To be a railway engineer, not only requires an accurate eye to take up the general aspect of the country, but at the same time to have a clear conception of its geological character. The level above the sea is too often overlooked, and considered a secondary matter; but it is all-important, as all main trunk lines for commercial purposes ought to have a branch communication with some sea-port. Nothing, indeed, is more common than to find

people suppose the summit of an inland district is greatly above the sea level, when in fact the rise is often inconsiderable. There are, perhaps, not many countries, where the general trending of the mountains is understood, through which railways could not be carried. No doubt "railway difficulties," as they are quaintly termed, which always more or less exist, are increased in hilly countries; but that route, which but a few years ago would have been deemed impracticable, now presents few obstacles to engineering skill.

In laying out a line of railway through a country, the gradients have been properly considered an important point in the adoption of the particular line. The word gradient, now in so common use, is well known to mean the proportion of feet of ascent or descent in a mile. An inclined plane is of course understood to mean every plane which is not level; and it is usual in describing railways to make use of the term inclination for ascent, as an incline of 1 in 101, or an ascent rising one foot in one hundred and one feet, which is the same as a gradient of 52 feet per mile. Beside the consideration of the gradients on the route, another principle of great importance to be kept in view is, to shorten the distance as much as possible between places to which a direct

communication is required. The result of experience in railway formation has already shown that circuitous routes not only increase much the expense, but do not afford the advantages required; beside which, the adoption of a curvilinear route too often, instead of a straight line, has had the effect of injuring the efficiency if not the general safety of the line.

The numerous plans of railways now before the public proceed, therefore, chiefly on the principle of a direct communication, and it is considered better for smaller towns to have a branch directly to the larger ones, than that a railway should perambulate a country, and diverge for their accommodation, at one point at a tangent, and at another by a semicircle, from the straight line.

It need hardly be observed, however, that in several cases it is impossible to avoid a curvilinear route, as in approaching domains, although there is no doubt that in many instances the objecting parties would ultimately obtain most advantage by permitting the straight line to have been adopted. Besides the advantage of having railways formed in direct, rather than in circuitous routes, a new feature seems to introduce itself into railway arrangements, which does not yet appear to be sufficiently understood; this is, the advantage of

having short lines of railway from town to town, and village to village, under local management, on the presumption that turnpike roads will soon entirely merge into railroads. On this plan the trunk lines proceeding in long distances would have feeding branches from every district; and one town being connected with another over the whole kingdom, would afford facilities of communication the present system never could give.

The want of having direct routes of railway communication fixed throughout the country has by many been considered an error in the railway system; which, however, from the number of lines, cannot prove any impediment either to general traffic or the convenience of passengers. In Ireland, commissioners were appointed to consider the subject of railways for that country, and certain lines have been proposed in conformity with their report; but from the limited extent of railways yet formed, there is not data sufficient to form any decided opinion of the system. Most of the continental railways have been planned under government control, but in Britain commercial enterprise seems likely to achieve every object desirable in respect to railway transit, and multiply the lines to accommodate every district in the United Kingdom.