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 FIRST EMPLOYMENT OF NATURAL FORCES. 225

problem of perpetual motion ; certain minds are always irresistibly attracted by the motion itself, by the first impression gained solely from external appearances, from the overpowering influence of which even the most accomplished cannot boast themselves to be entirely free. From attempts to cause motion the direct pro- duction of the corresponding force-actions slowly and step by step developed themselves. The popular idea which reverses the pro- cess makes the error of assuming the primitive inventor to have been a kind of Eobinson Crusoe, endowing him with a full acquaintance with modern ideas, while in reality he has both to find out the need of improvement and to recognise its possibility, before he even attempts to carry it out.

Men certainly required an enormous period before they began to develop what might be called the motoral side of the machine, before they attempted to use for working it other forces than their own muscular efforts. For this purpose they naturally turned first to the animals beside them, and made use of their muscles to save their own, but even this could not occur before the end of the long period during which the domestication of these animals was gradually taking place. Meantime men's energies were directed towards such improvements of their machinal arrangements as should enable the necessary number of workers to be diminished, thus increasing the capacity and efficiency of each single workman. 39 The primitive man looked only with fear upon the incomprehensible forces which he saw acting in the lifefess universe around him ; only very gradually did he lose his timidity sufficiently to attempt their utilisation. He used boats propelled by oars, as Curtius has shown philologically with great acuteness, long before he ventured to employ the wind-force beside him by using sails.

The rushing waterfall may well have appeared to him the most living thing in nature ; first, however, he noticed only its restless motion, the apparent unendingness.of which led him to employ it, e.g., in the Thibetan sacred \\iieels already mentioned. By degrees the idea of using the energy of this easily obtained motion came to him, and he carried it out in the scoop-wheel, as we have seen.

Meanwhile he gained some experience in such applications as the bow, of the great principle of storing energy in order that it may be used suddenly at the instant when it is required.

The bow of the archer is a machinal organ in which energy is K Q