TRENCHING AND SUBSOILING. 



159 



curvature of the vanes, and the great area of the wheel 

 (59 square yards), and we know that the pressure of the wind 

 increases more rapidly than the surface ; however, further 

 scientific experiments are required to fix the mechanical 

 yield of this machine. The above formula would give for a 

 rate of wind of 4 metres (13ft. 1^-in.) per second : 



T = 



3-14 16 x 4 2 x 1-293 x 4 3 x 70 

 2 x 9-808 x 100 



= 148-45, 



that is to say, 148 kilos (325 Ibs.) per second, almost 2 H.P. 

 The following table, calculated by the same formula, shows 

 for different rates of wind the probable power of Lucet's 

 motor, and the corresponding number of fans : 



The management of the motor and its displacement have 

 been well studied, but its orientation is tedious and very 

 defective, as, in the case of the wind not blowing perpen- 

 dicular to the direction of the headland, that headland 

 becomes triangular, and, in certain cases, might attain half 

 the area of a square block if the wind blows diagonally. 

 This defect might easily be remedied by fixing four rollers 

 under the framework, travelling on a circular rail, carried by 

 four rollers travelling on rolled joist girders in a similar 

 manner to a turn-table. Finally, although the machine is 

 only built for the purpose of trenching or subsoiling, its 



M2 



