CHAMBERS'S INFORMATION FOR THE PEOPLE. 



the same team could plough. In Scotland, the 

 grubbers chiefly in use are Tennant's and Secular's 

 one-wheeled ones, and Secular's and Kirkwood's 

 three-wheeled implements. In England, there 

 are, under the name of Cultivator, Coleman's and 



Johnston's, Bentall's Broadshare, Ducie's Drag, 

 &c. all of which are more complicated and heavy, 

 with more cast-iron in their construction than 

 those in Scotland ; but they work well when, 

 sufficient horse-power is applied to them. 



Fig. 4. Coleman's Cultivator. 



Fig. 5. Ducie Drag. 



Fig. 6. Tennant's Grubber. 



Fig. 7. Secular's Grubber. 



Fig. 8. Johnston's Skim Cultivator. 



We believe that more attention to the action of 

 this implement in the soil would result in the 

 construction of still greater improvements than 

 have hitherto been effected. It has never been 

 determined what form of tooth is best some 

 advocating a diamond-shaped point ; others, a 

 broad chisel ; and others, a duck-foot shape. We 

 prefer, after many trials, a broad chisel-point, four 

 inches at least, which, with the bend upwards, 

 works the soil very effectually, but requires con- 

 siderable force. 



Harrows. 



The early form of harrow was that of a board 

 of wood with wooden pins fixed in it. Iron then 

 took the place of wood for these teeth ; and at 

 length it was found that a framework of wood, 

 consisting of slots and bulls to use the language 



522 



Fig. 9. Biddell's Scarifier. 



of the joiner into which iron tines were driven, 



made a more effective implement. These harrows 



were generally made of a square form, and one 



was allotted to each horse. By making these of 



a rhomboidal shape, and 



coupling two together, and 



attaching a long tree to 



them, as in fig. 10, the 



irregular action on the soil 



of the former kinds was 



avoided, and each tooth 



operated on a separate 



portion of soil and at an 



equal distance from the 



one next it, as shewn in 



the dotted lines. These 



Fig. 10. 



harrows have long been made entirely of iron, 

 and are very effective on several sorts of land ; 





