The fact appears to be that canals flourish only where certain conditions exist. Where a large traffic can be conveyed in full boatloads; where the country is flat, and there are consequently few locks; where large vessels propelled by steam can be used; where works are so situated that the cost of collection or delivery can be saved; in such circumstances, canals are suitable for coal, chalk, cotton, stone, bricks, pig-iron, round timber, grain, &c., and such like goods carried in large quantities, or for short distances. They can, no doubt, when such conditions exist, be beneficially used at a low cost for carriage; but for traffic not large, or composed of a great variety of articles, which have to be collected in small quantities from different places, or to be distributed all over the country, canals cannot successfully compete with railways. Want of water in dry summers, interruptions from ice in winter, and diversity of gauges in locks and tunnels--all matters which add to cost--are great inconveniences, and grave objections to water carriage. Often carriage by canal necessitates the erection of warehouses for storing goods, which is saved by the transit of traffic by rail. The speed and despatch demanded by the modern necessities of trade have tended to throw upon the railway more and more of the traffic which formerly went by canals, as well as the increase in the traffic of the country. In Staffordshire, canal boats meet from all the principal towns such as Manchester, Liverpool, and parts of Yorkshire in the North, and London and Bristol in the South; _but no through traffic is exchanged_. All the traffic of Staffordshire in iron, hardware, chains, anchors, nails, &c., outwards, and grain, timber, spelter, bone, manures, &c. inwards, requiring speed, is carried by railways. Where the canal charges are equal to, or lower than, the railway rates, the railways and canals divide the traffic. Newly-opened collieries and works are now, as a rule, laid out for loading into railway wagons, not into boats, because railway stations and railway trucks give greater facilities for distribution of coal to all parts of the country. No doubt certain large canals--for example, the Aire and Calder, Bridgwater, and the Leeds and Liverpool--can be profitably worked in their exceptional circumstances, as they possess a plentiful supply of water, and traverse a long stretch of comparatively level country. Where such conditions exist for distances of fifty to sixty miles, canals may compete successfully for heavy traffic with railways.