MECHANICAL DIVISION OF SOILS. 95 



doubled the product. Its effect is similar to that produced 

 by the frequent treading in a foot-path ; and the observing 

 farmer will not have failed to notice, the single thread of 

 thick, green sward, which marks its course over an other- 

 wise almost barren field of sand or loose gravel. The thick- 

 ly-woven, emerald net- work, that indicates the sheep-walks 

 on similar soils, is principally due to the same cause. Those 

 portions of the pasture which have been thus compressed, 

 will be found to contain a thicker, greener herbage, which 

 is earlier in spring and later in autumn, and much more 

 relished by the animals cropping it, and apparently more 

 nutritive, than that on other parts of the field. 



Rollers are variously constructed. The simplest form is 

 a single wooden shaft, with gudgeons at each end, which rest 

 in a square frame, made by fastening four joists together ; a 

 tongue for drawing it being placed in one of its sides. A 

 box may be attached to this frame, for the purpose of hold- 

 ing stones and weeds picked up in the field, and for weight- 

 ing the roller according to the work required. The best 

 rollers, however, are of cast iron, made in sections of about 

 a foot in length. As many of these may be placed on a 

 single axle as are required. This division into short sections, 

 facilitates turning on the axle, either back or forward, and 

 prevents the unsightly and objectionable furrowing of the 

 earth, which occurs in turning with the long, solid roller. 

 Some are made of stone, but these are very liable to break, 

 and are equally objectionable in turning, as those made 

 of wood. 



The larger the roller, the greater is the surface brought 

 into contact with the ground, and consequently the more 

 level it leaves it. To accomplish this object without too 

 much increase of weight, rollers are frequently constructed 

 with heads at the ends, and closely covered like a drum. For 

 dividing compact, clay lumps, or scarifying meadows, they 

 are sometimes made with large numbers of short, stout, 

 angular teeth, projecting from the outer or rolling surface, 

 which penetrate and crush the clods, and tear up and loosen 

 the old turf and moss of meadows. 



THE CULTIVATOR 



Has a light frame, in the form of a triangular or wedge- 

 harrow, with handles behind, like those of a plow, and with 

 several small iron teeth in the frame, somewhat resembling 

 a double share plow. The teeth are usually of cast iron, and 



