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HISTORY OF ENGINEERING.

Rook I

At Vale Royal, about 64 miles from Hirmingham, the river Weaver is crossed by a viaductof stone; there are five arches each 63 feet span, and 60 feet in height, with parapets of12 feet, making the total height 72 feet above the river; the length of this viaduct is 456feet. Four miles beyond is the Dutton viaduct, composed also of twenty stone arches, eachspanning 60 feet. Where the railway crosses the Mersey and Irwell canal, there is a bridgeof stone having twelve arches; the two in the centre are 75 feet span; that which crossesthe canal is 40 feet, and the others are 16 feet 6 inches. The gauge of its way is 4 feet8^ inches, ruling gradients 1 in 177, rise in feet per mile 29. The total sum expended toJune, 1845, was 2,597,317/ , and the cost of working for the previous six months was96,336/.

The Newcastle and Carlisle: its length is 62 miles. In the first 42^ miles from thefirst named place, there is a rise of 10 feet 3 inches in a mile, or 1 in 515; in the next 6miles there is a fall of 5 inches in a mile ; and in the remaining distance, a fall of 390 feet,which is 30 feet in a mile, or 1 in 176. The level at Carlisle is 45 feet higher than atNewcastle. At Middle Gelt Bridge, near Brampton , is a viaduct which crosses twopublic roads and the river Gelt, at the height of 80 feet above the bed of the river, overwhich it is carried in an oblique direction, so as to prevent any bend in the inclination ofthe rails. The arches, which are three in number, are each 33 feet span, and are built atan angle of 45 degrees.

This railway was opened throughout on the 18th of June, 1839; the gauge of its railsis 4 feet 8.} inches, ruling gradients 1 in 106, rise in feet per mile 50, and cost per mile17,838/. The total sum expended to December, 1844, was 1,252,845/., and the cost ofworking for the previous six months 64,501/.

Newcastle and Darlington lias its termini at Rainton; it is in length 23 miles, and wasopened throughout 18th of June, 1844. The gauge of the way is 4 feet 8.^ inches, and thecost per mile 20,000/. The total sum expended to June, 1845, was 1,156,378/., and thecost of working for the previous six months 19,138/.

London and Birmingham Line was opened for public use throughout its entire length onthe 17th of September, 1838. The London terminus is at Euston Square, and occupies7 acres; a short distance beyond, at Park Street, Camden Town, is a plot of 33 acres ofground covered with buildings of various kinds for the use of the engines, waggons, car-riages, and luggage department. These two stations are united by a deep cutting, overwhich are seven bridges: the distance, which is 1J miles being an inclined plane, thecarriages are drawn up it by two stationary engines of 60 horse-power each, by means ofan endless rope wound round two cylinders; the trains on their arrival from Birmingham are propelled from Park Street to Euston Square by their own momentum.

The tunnel at Primrose Hill is 1120 yards in length, clear width and height 22 feet;the constructions throughout are of brick ; there are five ventilating shafts placed at regulardistances. Kensall Green tunnel, 3 miles beyond, is in length 320 yards.

The river Brent is crossed by a viaduct of seven arches, and a little beyond Watfordis another tunnel, 1 mile and 70 yards in length, 25 feet high, and 24 feet wide; beyondLeighton Buzzard is another tunnel, 272 yards long.

At Blisworth, about 5 miles from Castle Thorpe, is a cutting 2 miles in length, atan average depth of 50 feet, through blue limestone rock ; the quantity removed is saidto have been 1,200,000 cube yards. Five miles beyond, where the railroad passes underthe Old Watling Street, is Weedon tunnel, 418 yards long. To this succeeds the Kilsbvtunnel, 2398 yards in length. At Beechwood, near Ilainpton-in-Arden, is another tunnel,S00 yards long. According to a statement made by the engineer , Mr. Robert Stephenson ,the works were taken by public contract; the company provided blank tenders, to befilled up with schedules of prices, on which an estimate was founded : at the end of everymonth, the work was measured up, priced according to the list, and the amount paid, withthe exception of 20 per cent., which was withheld until the contract was finished accordingto the tenders.

The stone blocks for the chairs were delivered at 6s. each, and the price for theexcavation of ordinary materials was from Is. to Is. 6d. per yard ; the average price of thecutting 13 d. the highest price paid being 14d., which was clay, sand, and marl, with a lead of1^ miles only. If the lead was 3 miles, 17 d. or 2d. per mile extra for the leading. Throughthe rocks in Northamptonshire it was 2s. 3 d. per cube yard. The average lead upon thewhole line was 1-J mile; per yard was added for stock found by the company, aswaggons, rails, &c.

At Chalk Farm the company found all the materials, and paid the contractor 7 \d. per cubeyard, with a lead of about 600 or 800 yards ; he afterwards had Sd. One shilling and two-pence farthing per cube yard is the true cost, after adding interest of money, Sc c.: thisamount does not include the resodding of the slopes, nor any expenses which might arisefrom slips, &c.

The London clay is as easily worked in fine dry weather as any other material, but inwet weather the labour is exceedingly great. The waggons generally held two cubic