of the engineers, it would be capable of supporting a load of locomotives piled one on the top of the other over its whole surface, or that a line-of-battle ship might be suspended from it without danger.

The appearance of the bridge is very imposing. Could the reader stand upon the shores of the Isle of Anglesea, and view the entire spectacle, though but for a few moments, on some fine spring evening, he would retire with impressions of its magnificence which neither pen nor pencil can create. Extending in the far distance is the undulating landscape, varied by the rich tints of the woodland, and backed by rising hills; while the sun, approaching the verge of day,

"Wearied with sultry toil, declines and falls

Into the mellow eve; the west puts on

Her gorgeous beauties-palaces, and halls,
And towers, all carved of the unstable cloud.”

Stretching far away to the east and west, and glittering beneath the sun's rays, are the Irish Sea and St. George's Channel, connected by the Menai Straits; while the steam-vessel and the deeply-laden merchant-man wend their way along. In the distance, towards the Irish Sea, is the slender fabric of the Suspension Bridge, over which some seemingly Lilliputian vehicle and horses are passing. The small islands and rock which impede the progress of the water along the Straits serve to add interest to the scene. To the northward is the Anglesea column, erected by the inhabitants of the neighbourhood in commemoration of the gallant Marquis, who led the British cavalry at Waterloo; while about a hundred yards distant may be seen a humble, but touching monument, built by the workmen of the Britannia tower, as a tribute to the memory of some of their comrades who lost their lives during the construction of the bridge. On the south the view is bounded, at the distance of forty miles, by a range of mountains, the loftiest of which is the wellknown Snowdon. Between the base of these hills and the Straits, the little wooden town was erected which served for the accommodation of the artificers and workmen. And now, as we gaze upon this scene of mingled wonders and beauties, the deep-toned reverberation of a train rushing along the iron corridor of the bridge, smites upon the ear; and thus Science and Nature are mingled in harmonious contrast, and receive the grateful homage of every rightlyconstituted heart.

A Tabular view of some of the dimensions of the bridge, and some of the quantities of the materials employed in its construction, may serve to give a comprehensive idea of the entire work:

The successes of our great engineers may encourage all, at once to hope and to attempt. They have the mind to plan, and the hand to execute; and so have all men, though with different degrees of adaptiveness, and different spheres of action. The ever-varying contingencies of engineering operations are constantly opening new fields on which to exercise ability. In the erection of great works, and, to a still higher extent, in the contrivance and formation of moving machinery, the combination of theory and practice has to be accomplished in a way which affords room for all the resources of man. By accurate calculations and adjustment of opposing forces, and by practical skill in the mechanical details of construction, he must attain abundant strength united with the utmost possible economy of space and weight; and here lies the opportunity for the display of personal ability. There must be no waste of power, no useless and cumbrous weight; there must be a skilful counterbalancing of irregular strains, while the greatest pressure must be sustained by the points of greatest resistance. And thus it is that experience has entitled us to place implicit confidence in the scientific precision of our engineers. Every day we trust our lives and fortunes, without misgivings, in situations where a slight error in the calculations, or a small defect in the workmanship, would inevitably lead to catastrophes on which it is painful to allow the mind to dwell even for a moment. Let, then, past success in these departments of science and art encourage all to the prosecution of higher aims, and the attainment of permanent and more important results.

Far be it from it us to rank ourselves with those who would

circumscribe within some narrow bounds the limits of the exercise of man's inventive powers. To believe this would be inconsistent with the great fact of his nature as a progressive being; and though his resources and his sphere of operation are doubtless finite, yet we must not attempt to declare their boundaries. We avow no sympathy with the spirit manifested by the ancient Geographers, who drew the lines that marked the confines of the then known world upon their maps, and wrote "nil ultra" outside. Experience alone can decide the real obstacles that oppose the progress of scientific invention; for while some impediments are objective, and, from the constitution of nature, insuperable, others are subjective, and may be surmounted; and thus, that which seems impossible with one generation, is accomplished by the next. To know where is the barrier, is doubtless a difficult task; but what is left for man is, with zeal and perseverance, to prosecute the task of penetrating from the actual and the known into the broad expanse of the contingent and the unknown.

CHAPTER IX.

Permanent Way-Definitions-A Navvy's Explanation-Ballasting-Anecdote-" The Battle of the Gauges "-Origin of the present Gauge-Mr. Brunel's Gauge on the Great Western Railway-Reasons for the adoption of the Broad Gauge-Other Gauges Irish Railways-Relative advantages of the Broad and Narrow GaugesCost of the Gauges-Evils of a Break of Gauge-Combinations of Gauges-Proposals of Capt. Powell, Mr. Brunel, Capt. Simmons-Sleepers-Stone BlocksSetting the Stone Blocks-Transverse Wooden Sleepers-Chairs-Wooden KeysCost of Keys-Iron Keys-Rails first employed-Cast-iron and Malleable RailsProposal for Worming the Rails-Great Western Rails, Bearings, and Tracking— Experiments with Longitudinal and Transverse Sleepers-Curious results-Cast and Wrought Iron Road-Messrs. Barlow's Inventions-Relative Advantages and Cost of the old and new Method-Durability of Rails-Calculations on Belgium and English Lines-Duration and Renewal of the Permanent Way-Cost of Permanent WayAdvance in the Price of Iron-Anecdote of the great Iron Master's Wife, Lady Charlotte Guest-Daily Examination of the Permanent Way-Squinters-Arrangements during the Repair of the Permanent Way-A near Run.

AVING briefly described the chief works in the construction of a railroad, the permanent way, as it is designated, comes under consideration. The origin of this technical name is not obvious; for the term is applied to that portion of a railway which is the least permanent of the whole, and which requires continual watchfulness and frequent repairs to maintain in efficient working condition. The word, however, is not inappropriately employed in contradistinction to the temporary way, which is laid down in the first instance to facilitate the construction of the line. A definition of the term, which was once given by a ganger to Mr. Brunel and one of his' engineers, may perhaps throw some light upon the subject. Shortly before the opening of the Great Western line between Maidenhead and Twyford, the engineer-in-chief visited the works. A siding had been made, leading along an incline to a gravel-pit; from which ballast had been brought for the permanent way, and Mr. Brunel was somewhat annoyed at finding that it had not been filled up. The ganger, who was standing near, was accordingly taken to task; and the inquiry made how it was that the work