158 POKTABLE WIND MOTOKS APPLIED TO 



second ; assuming the vanes normal to the direction of the 

 wind, Button's formula, used for inclined surfaces, gives a 

 value rather higher 62 feet to 65 feet, that is to say, a gale. 



Orientation. To change the orientation of the motor, the 

 extremity of the iron girder Q is lifted by a screw-jack, and, 

 under the centre of the beam, two solid wooden blocks with 

 a pivot are placed ; four axle arms are placed on the main 

 frame A in a radiating direction, four supplementary wheels 

 are fixed on them, transforming the frame into a kind of 

 turn-table; the orientation is then done by hand as in the 

 case of locomotive engines. 



Work. We give below the figures obtained by the 

 inventor when trenching his property. We are at present 

 unable to authenticate them, but intend to verify them with 

 Prony's mechanical brake. When the rate of the wind does 

 not exceed 20 feet per second all the vanes are left on, and the 

 rate of the cable varies between 4-6 to 7 '8 inches per second, 

 the area ploughed is 72 to 120 poles per day, to a depth of 

 19 \ to 24 inches. When the rate of the wind increases, the 

 vanes are gradually removed, so that twelve to fourteen only 

 remain on when the rate of the wind reaches 26 feet, eight 

 to ten when it reaches 32 feet, so that the .power obtained 

 does not exceed 7 to 8 B.H.P. 



Observations. The general disposition of the framework, 

 and of the vanes, allow an easy motion of the wheel, 

 although the power obtained is fairly great. This is probably 

 due to the curvature of the vanes, the mechanical yield of 

 which seems to be greater than that of most wind-mills. If 

 we consider the formula generally adopted to represent the 

 motive power of wind-motors : 



T _ S x p x v 3 



~*r 



T, being the theoretical work the wind is capable of 



giving ; 



S, the area of the vanes ; 



/>, the weight of a cubic metre of air, i.e., 1-293 kilos.; 

 v, the rate of wind in metres per second ; 

 </, the acceleration due to gravitation, i.e., 9*808 metres. 



According to the experiments of JSmeaton and Coulomb, the 

 mechanical yield would be, for ordinary wind-mills, 45 per 

 cent. ; for American wind-mills, 57 per cent. We may admit 

 a yield of 70 per cent, for Lucet's motor on account of the 



