Book IV. 



SCARIFIERS AND GRUBBERS. 



403 



the use of the scarifier much too far. We think it is a sufficient illustration of its value that it may be 

 used in stirring lands on which potatoes or turnips have grown, or that has been ploughed in autumn or 

 during winter, so that a crop may be sown in spring without farther use of the plough. In working 

 fallows, and preparing for turnips and potatoes, it may save two or three furrows. {Supp. Ency. Brit, art 

 Agr. and Farm. Mag.) 



2656. Wilkies parallel adjusting brake, or cultivator {Jig' 322.), appears to us decidedly 



the most perfect implement of this description. The prongs of such implements, 

 mechanically considered, are bent levers {Jig. 323.), of which the fulcrum is at a, the 



power at b, and the weight ^ ^ 



or resistance at c. The im- ^._.,^ 4 ^^^ y'^^^^^'^ 



provement of Mr. Wilkie y>-- vf ? P yi^^^ /) 



consists in adopting a curve p ^>^^a. ^'::::^^^ -r d 



{d b), for the resisting part .j.^^^^^^ ^ 



of the lever, and thus bringing into action the principle of tension, instead of mere 

 resistance to fracture in the resisting part of the lever. {Gard. Mag. vol. v. p. 655.) 

 The parallel movement has the advantage of instantaneously adjusting the implement to 

 any depth that may be required. Besides the ordinary purposes of a cultivator, this brake 

 or harrow may serve the other tillage purposes following : 1. By attaching tines with 

 triangular feet, it makes a scarifier ; or, in place of tines, one large triangular blade 

 suspended from each of its extremities or angles. 2. By substituting cutting wheels in 

 place of tines, it is converted into a sward cutter. 3. From its extreme accuracy of 

 adjustment it will make an excellent drill, or ribbing machine, and may be made to sow 

 at the same time. And 4. and finally, if steam is destined ever to supersede the labour 

 of horses in drawing the plough, this machine, from its peculiar formation and mode of 

 management, will afford the greatest facility for trying the experiment, as it may be made 

 to take a number of furrows at once. 



2657. FinlaysorCs self-cleaning cultivator, or harrow {Jig- 324.), is formed of iron, and. 



according to the inventor, has the following advantages : 1 . From the position in which 

 the tines are fixed, their points {a a a a a) hanging nearly on a parallel to the surface of 

 the land, it follows, that this implement is drawn with the least possible waste of power. 

 2. From the curved form of the tines, all stubble, couch, &c. that the tines may encounter 

 in their progress through the soil, is brought to the surface, and rolled up to the face of 

 the tines ; when it loses its hold, and is thrown off {at b b b b b), always relieving itself 

 from being choked, however wet or foul the land. 3. The mode by which this harrow 

 can be so easily adjusted to work at any depth required, renders it of great value ; this is 

 done as quick as thought by moving the regulator (c) upwards or downwards between 

 the lateral spring (de) ; and by each movement upwards into the openings {J'g h i k), 

 the fore tines {II 1 1) will be allowed to enter the soil about an inch and a half deeper by 

 each movement into the diflferent spaces, until the regulator is thrown up to (e), when 

 the harrow is given its greatest power, and will then be working at the depth of eight or 

 nine inches. Also the axletree of the hind wheels is moved betwixt and p, a space of 



Dd 2 



