PROBLEMS OF MOVEMENT Economic movement may be divided into five great categories, namely, movement by air, by water, by rail, by road and by pack. Each may be divided into two sub-categories. Thus, air movement by transport lighter and heavier than air; water movement into sea transport and inland water transport; railway movement into broad and narrow-gauge lines; road movement into transport by wagon and lorry, and pack movement into human and animal porterage or carriage. I do not here intend to examine movement by air and water, and, as regards the other three categories, I will limit my examination to their use in undeveloped countries, more particularly within the Empire, and I will start with the railway. _The Railway._ The country through which a railway is built may be divided into three economic areas:— (i) A belt about eighty miles in width, through the centre of which the railway runs. (ii) Two belts, each about twenty miles wide, extending on the flanks of the central belt. (iii) The whole of the country concerned, excluding the above three belts. Whether the prosperity of the country is based on minerals, cattle, or cereals, the first belt is normally prosperous, the second two less prosperous, and the remainder of the country unremunerative. To bring the whole country up to the prosperity of the first belt demands a railway every eighty miles. Obviously, in an undeveloped country, to build railways every eighty miles is prohibitively costly, but as nearly every nation in the world is prepared to spend millions of pounds on the construction and maintenance of railways and rolling stock, and often with little reference to the law of supply and demand, it is advisable, I think, briefly to examine the question of cost. The cost of a railway decreases as the load increases; the load must, consequently, be sufficient to pay for the capital expenditure entailed in constructing the line and also its maintenance. The cost of the Nigerian railways was £11,000 per open mile; the estimated cost of new construction in the Gold Coast lies between £13,000 and £17,000 per mile. For railways costing as much as these, and the figures are not abnormally high, to pay, the country they traverse must not only be fertile or rich in minerals, but thickly inhabited.