IO4 THE FIRST BOOK OF FARMING 



the surface. They also tend to drag out coarse 

 manures when plowed in. 



The original and more common form of the 

 spring-toothed harrow is a floating harrow when 

 at work. That is, it rests on 'the points of the teeth 

 and is dragged or floated over the ground. A 

 newer form of spring-toothed harrow, sometimes 

 called the fallow cultivator, is mounted on high 

 wheels and its action is largely controlled by them. 

 This form of harrow is claimed to-do much better 

 work than the floating harrow and may in a large 

 measure displace the rolling cutter. The weight of 

 this harrow is entirely taken from the soil except 

 in the wheel tracks, and the entire action is that of 

 pulverizing and lightening the soil. 



Spike-toothed harrows (Fig. 56). The teeth of 

 these harrows are round, square or diamond-shaped 

 spikes fastened into a wood or iron frame. The 

 teeth are set in a vertical position or are inclined to 

 the rear. These harrows are shallow in their action ; 

 they run easily but tend to compact the soil more 

 than the other types and are therefore better ad- 

 apted to loose soils and to finishing off after the 

 work of the deep cutting harrows. They are also 

 used for covering seeds. 



Coulter-toothed harrows. The coulter-toothed 

 harrows (Fig. 57) have teeth resembling the coul- 

 ter of a plow twisted or bent into various shapes. 

 The Acme is a good example of this class of har- 

 row. It cuts, turns and pulverizes the surface soil 

 somewhat after the manner of the plow. It pre- 



