the snow which represents the accumulated rainfall of the Why Glaciated Regions have Abundant Water Power.—(1) Falls and Rapids.—The parts of the world which possess the most favor able combination of rugged relief, many lakes, and abundant rainfall have all been glaciated. This is because during the cold, stormy glacial period in the earth's history, great glaciers spread out from cool, well-watered elevated regions. As they moved slowly forward they changed the topography, turning rivers out of their courses so that they formed numerous falls and rapids, and causing many great hollows which are now filled by numerous lakes. Niagara Falls, the finest source of water power in the world, came into existence because ice closed the ancient outlet of Lake Erie. The lake over flowed along a new course, which caused it to tumble over a cliff. Hence to-day Niagara Falls furnish light and power to multitudes of people. They might furnish three million horse-power, or nearly a tenth of all that is used in the United States, if the governments of the United States and Canada had not imposed restrictions in order to preserve the wonderful natural beauty of the tremendous water fall.
In New England, Wisconsin, and similar regions the ancient glaciers did not cause such striking falls as at Niagara, but gave rise to many smaller ones, and to frequent rapids which can easily be dammed. This has stimulated the growth of such industrial cities as Manchester, Nashua, Lowell, and Lawrence on the Merrimac River, Holyoke, Springfield, and Hartford on the Connecticut, and a string of small cities on the lower Fox River in Wisconsin (see Fig. 42.) In mountainous regions the ancient glaciers deepened the valleys and steepened their walls so that tributary streams often enter the main valley in a series of cascades which can readily be utilized for power. In Switzerland and Norway, where glaciers persisted in valleys for thousands of years after the continental glacier had re treated, such falls are numerous, and are one reason for the pre eminence of those countries in the use of water power.
(2) Glacial Lakes.—Over 90 per cent of all the lakes in the world are due to glaciation. In some cases, such as the Great Lakes, the Finger Lakes of Central New York, and the famous lakes at the foot of the Alps in northern Italy, the glaciers dug out enor mous hollows which were filled by water when the ice melted. In other cases, such as hundreds of lakes in New England, Wisconsin, Canada, and Russia, the ice laid down great masses of rock and soil called moraines, and these caused lakes by acting as dams. Wherever such lake regions have sufficient relief they afford all the conditions needed for the development of abundant water power. The glacial lakes, falls, and rapids of New England, for example, are one of the chief reasons why New England early developed its manufacturing industries and is still able to maintain its position although it has neither coal nor raw materials.
The Value of Water Power in Switzerland.—In the use of water power Switzerland is even farther advanced than New England. To-day the power used by practically all the street railways and by the bulk of the industrial enterprises in that country comes from waterfalls. The railways, too, are giving up coal and using hydro electric power, that is, power derived from electricity generated by the streams that pour down from the mountains. The loom of the lace-maker and the machine of the watchmaker in the home are also being driven by hydro-electric energy. Such energy even goes into the barn and house of the peasant. Thus grain is threshed, butter is churned, water is pumped, food for cattle is prepared, and the farmer is relieved of his most arduous labor. Much of this develop ment of water power is due to the wise policy of government regula tion and the payment of royalties to the state by users of the water.
The Growth of the Use of Water Power.—In view of the great demand for power it seems strange that only about one-sixth of the possible water-power of this country has been developed. We must remember, however, that many of the best water-power sites have been unavailable because located in mountainous regions where the rough ground affords little opportunity for factories and houses, and where transportation is expensive. At last, however, hydro-electric methods of transmitting power have so developed that not only is a 400-mile line in operation in southern California, but engineers are considering the construction of a 700-mile line in Africa from the Victoria Falls of the Zambesi to the mines at Johannesburg.
No water power site can hope to rival Niagara. The size of the river, the sudden fall from a great height, the regularity of the rain fall, and the steadiness of the river because of the great reservoirs back of it are all advantages of the highest order. In addition to this the falls are located in a comparatively level region where transportation is easy and cheap, and where there is plenty of room to establish factories and build houses. And finally, the falls are in a district where the population is dense, energetic, and progressive, and which even without water power would be one of the world's great manu facturing regions.
The nearest rivals of Niagara are both called the Victoria Falls. One, on the Zambesi, is over twice as high as Niagara and carries an enormous volume of water. The other, on the River Iquassu on the boundary between Brazil and Argentina, and only 16 miles from Paraguay, is 215 feet high and has a series of twenty falls separated by islands just as Goat Island separates the American and Canadian Falls at Niagara. Neither of the two Victoria Falls has yet been used for water power because bore located in an unfavorable climate far from manufacturing centers,