98 



SPECIAL SUBSOILERS. 



the steam-engine (fixed point). The cable passes over the 

 loose pulley of the mole-plough (Fig. 61) the other extremity 

 winding on the drum. With such an arrangement the 



Fig. 61. Fowler's Mole-plough. 



traction on the plough is 

 doubled, but the speed falls 

 to half. 



The work done by -Fowler's 

 machine depends on the shape 

 given to the mole ; that shown 

 in Fig. 62 is used to make, 

 by compression, underground 

 drains at a depth varying from 

 27J inches to 3ft. 3in. These 

 drains last from fifteen to 

 thirty years, and the cost is 

 only 10s. per acre. But this 

 kind of subsoiler can only be 

 used in clayey soils free from 

 stones. For ordinary sub- 

 soiling the mole may be re- 

 placed by subsoiling teeth. 

 Ransomes used to make a special subsoiling machine called 

 Beauclerc's Archimedian subsoiler; this machine resembled 

 that of Reed-Slight, but at the rear of the share an Archi- 

 median endless screw was fixed revolving round an axle. 

 According to the inventor, the strip of soil cut by the 

 share would revolve this screw, and thus stir the sub- 

 soil, lifting it to a certain height to let it fall crumbled 



Fig. 62. Mole of Fowler's plough. 



