Of Iron Girder Bridges there have been many fine specimens erected since the railways have been begun. Except a few small ones which have been constructed at Roorkee, they have all been made up in England, sent out in pieces, and erected on the spot. I especially commend to your notice the paper on the Tonse Bridge, in the ‘Professional Papers,’ as giving an excellent idea of the difficulties of this kind of work.
So much, then, for bridges. I now turn to the very important subject of _Roads_. Great progress has been made within the last twenty years in providing India with roads, but thousands of miles are still wanted before the road system can be considered anything like complete. The cost of carriage in many parts of the country is still enormous, owing to the wretched state of the unmetalled tracks, and whole districts may be starving while plenty reigns in those adjoining, owing to the same cause. However, these are questions with which the young engineer at least has seldom anything to do; his work begins when the construction of the road is decided upon. The rules regarding the laying out and construction of roads are of course the same in India as in other countries. I will only dwell on characteristic specialities. Of the construction of the earthwork I spoke in my last lecture. The Metalling employed is kunkur, already described, and various kinds of stone used in macadamizing in the ordinary way. Heavy iron or stone rollers, drawn by bullocks, are usually employed, but steam road-rollers have lately been introduced in Calcutta, Bombay, and even the wilds of the Central Provinces.
The Grand Trunk Road[B] runs from Calcutta to Peshawur, a distance of 1600 miles, passing through the Rajmehal hills by some very heavy works, then on to Benares, Allahabad, Cawnpore, and Delhi, thence to Umballa, and Lahore, and Jhelum, by massive embankments; thence for the last 160 miles to Peshawur it is carried by some of the heaviest and most difficult works in the world. The designer and constructor of the whole line was Lieut. (now Colonel) A. Taylor, R.E., C.B., director of the attack at the siege of Delhi.
The Hindostan and Thibet road is another fine work which you will find described in the books. It is carried right through the hills from Kalka at the foot, viâ Simla, up the valley of the Sutlej, and is about 300 miles long; but only the first 60 miles are open for wheeled traffic. Sometimes it is carried but little above the level of the river, then it ascends a hill-side by a series of steep zigzags, then it goes boldly through a rock by a heavy cutting or short tunnel, then through a magnificent forest of deodars, then by the side of a vertically scarped hill, 2000 feet down, in which the road is either blasted out of the solid rock or supported by iron bearers let into the rock, and carrying a timbered floor. Probably no road in the world offers such fine scenery to the traveller. The officer who did most of the work on this road was Major Lang, R.E., my _locum tenens_ at Roorkee. Before leaving the subject of roads, I may draw your attention to two or three instruments used in tracing hill roads, which you will find described in the ‘Treatise’—the Madras Clinometer, and De Lisle’s Clinometer.