WINDMILLS 299 



John Burnham is said to be the inventor of the American wind- 

 mill. L. H. Wheeler, an Indian missionary, patented the Eclipse 

 in 1867. The first steel mill was the Aermotor, invented by T. O. 

 Perry in 1883. 



The windmills still most common in Europe are of the Dutch 

 type, with their four long arms and canvas sails. These sails 

 usually present a warped surface to the wind. The degree of the 

 angle of the sails with the plane of rotation, called the angle of 

 weather, is about 7 at the outer end and about 18 at the inner. 

 The length of the sails is usually about 5/6 the length of the arms, 

 the width of the outer end 1/3 the length, and the width of the 

 inner end 1/5 the length. It is seen that the total projected area 

 of sails is very small compared to the wind area or zone carrying 

 the sails. Quite often these wheels are 120 feet in diameter and occa- 

 sionally 140 feet. In comparing these mills with the close, compact 

 types of American makes a very great contrast is to be drawn. 



Among the men who have done the most experimenting in 

 windmill lines are Smeaton, Coulomb, Perry, Griffith, King, and 

 Murphy. The names are given in order of date of experimenting. 

 The more prominent among these are Smeaton, Perry, and Murphy. 

 Probably Perry did more for the windmill than any of the others. 

 Prof. E. H. Barbour is noted for his designs and work with home- 

 made windmills. 



423. Home-made windmills. Professor Barbour made 

 an extensive study of home-made windmills and has had 

 a very interesting bulletin published on the subject. He 

 has classified them as follows : 



1. Jumbos (Fig. 202). This type consists of a large fan-wheel 



placed in a box so the wind acts on the upper fans only. 



2. Merry-go-rounds. Merry-go-round mills are those in which 



the fans in turning toward the wind are turned edgewise. 



3. Battle-ax mills (Fig. 203). These are mills made with fans of 



such a shape as to suggest a battle-ax. 



4. Holland mills. Somewhat resembling the old Dutch mill. 



5. Mock turbines (Fig. 204). Resembling the shop-made mill. 



6. Reconstructed turbines (Fig. 205). Shop-made mills rebuilt. 



These mills, although of low power, are used exten- 

 sively in the West Central States. Most of them are fixed 



