instantly overpowered by conflicting feelings,-by the recollection of the endless time he had been imprisoned-and by the joy of his release, he sat down on a log of timber, and, putting both his hands before his face, he began to cry aloud most bitterly. The English "navvy" sat himself down on the very same piece of timber-took his pit-cap off his head-slowly wiped with it the perspiration from his hair and face-and then, looking for some seconds into the hole or shaft close beside him through which he had been lifted, as if he were calculating the number of cubic yards that had been excavated, he quite coolly, in broad Lancashire dialect, said to the crowd of French and English who were staring at him as children and nursery-maids in our London Zoological Gardens stand gazing half terrified at the white bear, "YAW'VE BEAN A DARMNATION SHORT TOIME ABAAOWT IT!" In the construction of the London and North-Western Railway, the contractor at Blisworth also failed and also died. Besides the perpendicular cutting which he had undertaken to execute, there was, on the surface of the rock through which it now passes, a stratum of about twenty feet of clay of so slippery a nature, that for a considerable time, in spite of all efforts or precautions, it continued to flow over into the cutting like porridge. The only remedy which could be applied was, at vast labour and expense, to remove this stratum for a considerable distance, terminating it by a slope at a very flat angle, all of which extra labour, trouble, and expense, we may observe, is not only unseen but unknown to the traveller, who, as he flies through the cutting, if he looks at the summit at all, naturally fancies that it forms the upper extremity of the work. In the construction of the tunnel at Watford an accident occurred of rather a serious nature. A mass of loose gravel concealed in the chalk, slipping via the shaft into the tunnel, suddenly killed eleven men, besides letting down from the surface a horse and gin. CUTTINGS. 9. In passing through the consecutive cuttings of a great railway, the traveller usually considers that those through rock must have been desperate undertakings, infinitely more expensive than those through clay. The cost of both, however, is nearly equal; for, not only does the perpendicular rockcutting require infinitely less excavation than the wide yawning earth one of the same depth, but when once executed the former is not liable to the expensive slips which subsequently occasionally afflict the latter. In determining whether the line should proceed by tunnelling or by cutting, the engineer's rule usually is to prefer the latter for any depth less than sixty feet; after which it is generally cheaper to tunnel. If, however, earth be wanted for a neighbouring embankment, it becomes of course a matter of calculation whether it may not be cheaper to make a cutting instead of what abstractedly ought otherwise to have been a tunnel. In the construction of the Tring cutting alone of the present London and North-Western Railway, there were excavated 1,297,763 cubic yards of chalk, of which about fifteen cubic feet weighed a ton. EMBANKMENTS. 10. Besides contending with water above ground as well as below, the constructor of a railway is occasionally assailed by an element of a very different nature. For instance, when the Wol verhampton embankment of the present London and NorthWestern Railway, at vast trouble and expense, was nearly finished, it was observed first to smoke, then get exceedingly hot, until a slow mouldering flame visible at night appeared. The bank began to consume away, and the heat continued until it actually burned the railway sleepers; at last, however, it exhausted itself. The combustion was caused by the quantity of sulphuret of iron or pyrites contained in the earth of the embankment, which, having been baked by the fire, will probably never slip. 11. It would be tedious, and indeed impossible, to detail the various works which a railway engineer has to superintend in the construction of the line, in the laying down of the rails or 66 permanent way," and in the subsequent, or rather simultaneous, erection of the various station-houses, storehouses, workshops, &c. &c., the interior of which we shall soon have occasion to enter. An idea, however, of the magnitude of his operations may be faintly imparted by the following brief abstract of a series of calculations made by Mr. Lecount, one of the engineers employed in the construction of the southern division of the present London and North-Western Railway, and the writer of the article Railways' in the Encyclopædia Britannica.' The great Pyramid of Egypt was, according to Diodorus Siculus, constructed by three hundred thousand-according to Herodotus by one hundred thousand-men; it required for its execution twenty years, and the labour expended on it has been estimated as equivalent to lifting 15,733,000,000 of cubic feet of stone one foot high. Now, if in the same manner the labour expended in constructing the Southern Division only of the present London and North-Western Railway be reduced to one common denomination, the result is 25,000,000,000 cubic feet of similar material lifted to the same height; being 9,267,000,000 of cubic feet more than was lifted for the pyramid; and yet the English work was performed by about 20,000 men only, in less than five years. Again, it has been calculated by Mr. Lecount that the quantity of earth moved in the single division (112 miles in length) of the railway in question would be sufficient to make a foot-path a foot high and a yard broad round the whole circumference of the earth! the cost of this division of the railway in penny-pieces being sufficient to form a copper kerb or edge to it. Supposing therefore the same proportionate quantity of earth to be moved in the 7150 miles of railway sanctioned by Parliament at the commencement of 1848 (Vide Parliamentary Returns), our engineers within about fifteen years would, in the nstruction of our railways alone, have removed earth suffi t to girdle the globe with a road one foot high and one dred and ninety-one feet broad! Abandoning, however, speculations of this nature, we will conclude our slight sketch of the principal works required for a railway by a few data, exemplifying the magnitude of the Britannia Bridge over the Menai Straits, the construction of which has been intrusted by its well-known inventor to the very able and experienced management of Mr. Frank Forster. The dimensions of this straight wrought-iron aërial gallery, through which passengers and goods are to travel by rail, are— Total length of bridge, divided into 4 openings— Quantity of masonry in the towers and abutments. The cost of the scaffolding now in use about the bridge has exceeded Feet. In. It would, we conceive, be impertinent to dilute the above facts by a single comment. THE CHIEF ENGINEER. As the selection of an engineer-in-chief, competent to determine the best line for a projected railway to take, the mode in which it should be constructed, and, lastly, to execute his own project-deviating from it with consummate judgment according to the difficulties, physical, moral, and political, which, sometimes separately and sometimes collectively, suddenly rise up to oppose him-is a point not only of vital importance to the success of the undertaking, but in the undertaking is the first important point to be decided, it would, we were aware, have apparently been the most regular to have commenced the present chapter with this subject. We conceived, however, that instead of there detailing the qualifications necessary for the duties required, it would save us very many words, and our readers as much time, if we were to defer the consideration of that subject until a brief outline of those duties should, without comment, practically explain the qualifications required. If the United Kingdom had only projected the construction of one or two great arterial railways, we might naturally have expected that the few competent engineers necessary would readily have been obtained; but when we consider the number of railways that were simultaneously created, the surveys, plans, sections, and other preparations that were necessary, the magnitude of the works of various descriptions that were to be constructed in each, it must evidently to many be a subject of astonishment that there should have been found on the surface of our country not only the amount of engineering talent necessary for the execution of such vast works, but an amount which may truly be said to have exceeded the demand. "black The curious historical fact, however, is, that the amount of engineering talent thus suddenly required existed not on the surface of our country, but, on the contrary, many hundred fathoms beneath it. The brilliant talents that were required were diamonds," without metaphor embedded in the bowels of the earth. Science called her spirits from the vasty deep, and in obedience to her commands there arose out of the shafts of our coaleries, and from beneath, the bottom of the Thames— OLD GEORGE STEPHENSON, who had served his articles of apprenticeship in a coal-mine, for many years working at the engines both above ground and below; ISAMBARD BRUNEL, whose principal experience had been acquired in the construction of the Thames Tunnel; JOSEPH LOCKE, a colliery-viewer, who had served his apprenticeship below ground; ROBERT STEPHENSON, brought up as a coal-miner, served his apprenticeship at Killingworth colliery ; FRANK FORSTER had worked for seven years as an apprentice in a coal-mine; NICHOLAS WOOD, ditto; CHARLES LEAN, ditto; And a crowd of similar genii, all slaves of the same lamp, or "Old Davy," as they term it. |