THE CONQUEST OF NATURE 



were undertaken by the Dutch philosopher, Servinus. 

 The use of the windmill in Holland as a means of gen- 

 erating power doubtless suggested to Servinus the possi- 

 bility of attaching a sail to a land vehicle. He made 

 the experiment, and in the year 1600 constructed a 

 sailing car which, propelled by the wind, traversed the 

 land to a considerable distance, on one occasion con- 

 veying a company of which Prince Maurice of Orange 

 was a member. But his experiments have seldom 

 been repeated, and indeed their lack of practical feasi- 

 bility scarcely needs demonstration. 



The utility of the wind, however, in generating the 

 power in a stationary mechanism is familiar to everyone. 

 Windmills were constructed at a comparatively early 

 period, and notwithstanding all the recent progress in 

 the development of steam and electrical power, this 

 relatively primitive so-called prime mover still holds 

 its own in agricultural districts, particularly in its appli- 

 cation to pumps. A windmill consists of a series of in- 

 clined planes, each of which forms one of the radii of a 

 circle, or spokes of a wheel, to the axle of which a gearing 

 is adjusted by which the power generated is utilized. The 

 wheel is made to face the wind by the wind itself blowing 

 against a sort of rudder which projects from the axis. 

 The wind blowing against the inclined surfaces or 

 vanes of the wheel causes each vane to move in accord- 

 ance with the law of component forces, thus revolving 

 the wheel as a whole. 



It has been affirmed that the Romans had windmills, 

 but "the silence of Vitruvius, Seneca, and Chrysostom, 

 who have spoken of the advantages of the wind, makes 



[68] 



