Page:The Canal System of England.djvu/60

 The greatest drawback to Inland Navigation is the slow rate of speed at which goods can be carried. The speed of boats on canals is regulated by several conditions, such as—the sectional area of the canal, radius of curve, changes of level, &c.—and thus even where locks and other obstructions are absent, a greater speed than 4 to 5 miles per hour is impossible without great damage being done to the banks. Hence the dimensions of the canal are of the first importance, since they not only fix the size of the boats, but also to a very great extent regulate the speed and economy with which it may be navigated.

The number of locks naturally forms a most important factor in determining the speed at which a boat will traverse a given distance. It has been estimated that on the English canal system there is one lock to every 1·37 miles of waterway, and that a delay of at least six minutes is incurred at each change of level. All these small losses of time reduce the total speed, and it is on the claim of quicker delivery that the chief advantage of the railway over the canal rests, a claim which we propose to consider for a short space.

Between Gloucester and Birmingham the goods despatched by river and canal are delivered as expeditiously as those sent by railway. Sir James Allport, in his evidence before the Select Committee of 1883, said that the