USE Ol- 1 THE ROLLER. 



145 



Fig. 21. 



It leaves the ground mellow like the fork, and in good 

 condition for the cultivation of crops. 



457. The harrow, (Fig. 21,) is an 

 ancient implement, and is most com 

 monly used after the plough, to 

 break down and mellow or pulverize 

 the furrow slice. It should be moved 

 rapidly over the soil. It has been 

 very much improved within a few 

 years. 



458. The cultivator, (Pig. 22,) may 

 properly be regarded as a modified 

 form of the harrow, but it is much 

 better than the harrow, 



because with its plough 



shaped teeth, it lightens 



up and mellows the 



surface soil, instead of 



pressing it down hard, 



as the harrow is apt to 



do every where except Fig. 22. 



on new, rough land. 



459. The roller is often used to pulverize the surface 

 soil. It has so large a surface to rest on the soil, that it 

 crushes and breaks up clods without hardening the lower 

 strata. 



460. In laying down lands to grass, it is often useful 

 in pressing down small stones, so as to get them out of 

 the way of the scythe. It is often useful, also, 011 newly 

 sown grain, and hastens the germination of seeds, by 

 preserving the moisture around them. 



4G1. But clayey soils should never be rolled except 

 when they are perfectly dry, and for the purpose of 



