The trans-Siberian railway, which is the longest straight line of steel in the world, was built largely as a wheat-conveyor. So were the railways of western Canada, Argentina, and India. Ever since the advent of the Reaper wheat has been the prolific mother of railways and steamships. While the rice nations are still putting their burdens on ox-carts and on the backs of camels and elephants, the wheat nations have built up a system of transportation that is a daily miracle of cheapness, efficiency, and speed. This system is not yet finished. A new line of steamships is about to be set afloat between Buenos Ayres and Hamburg. The Erie Canal is being re-made, at a fabulous cost, so that a steamer with 100,000 bushels of wheat can go directly from Buffalo to New York. And an adventurous railway is now pushing its way north from the wheat-fields of western Canada to the unknown water of Hudson Bay, whence the wheat will be carried by boat to London and Liverpool. To-day it is not the long haul of wheat, but the short haul, that is more expensive. It is cheaper to carry wheat from one country to another than from the barn to the nearest town. The average distance that an American farmer has to haul his grain is nine and a half miles, and the average cost of haulage is nine cents per hundred pounds. Thus it has actually become true that to carry wheat ten miles by wagon costs more than 2,300 miles by steamship. Such is the tense efficiency of our wheat-carrier system that a bushel of grain can now be picked up in Missouri and sent to the cotton-spinners of England for a dime. Associated with this transportation problem was the matter of storage. There was no sort of a building known to man, fifty years ago, in which a million bushels of wheat might be conveniently kept. An entirely new kind of building had to be invented. All the wheat barns were overflowing. All the warehouses were outgrown. The difficulty was to make a huge building that could be quickly filled and emptied. Then, at the precise moment when he was needed, an inventor, F. H. Peavey, appeared with a device for elevating grain--an endless carrier to which metal cups were fastened. From this idea the _elevator_ was born. [Illustration: MAMMOTH WHEAT-FIELD IN SOUTH DAKOTA WITH TWENTY HARVESTERS IN LINE]