On Agricultural Mechanics. 123 



6 inches, the same as in Scoular's. On the points of these teeth, either 

 chisel-shaped or duck-foot or triangular edges for paring are slipped, 

 the form of the tooth on which they slip being such as to hinder these 

 teeth from slipping round. This, with the form of the teeth, is repre- 

 sented in the figure; the teeth for paring are much more pointed 



Kirkwood's. Finlayson's. Biddell's. Uley Cultivator. 



than those of Biddell's, with which they are compared in the annexed 

 figure. The implement has been tried for paring as well as for stirring, 

 and is found to move the whole surface of the ground most perfectly. 



3rd. The frame-work does not, as in Finlayson's harrow, consist of a 

 series of cross-bars, into two of which the teeth are fixed in two rows, 

 but it is as in the annexed figure; each tooth having its own bar, to 

 W'hich it is affixed, and not being attached in a direction across the bar, 

 but in the direction of its length, so that any strain on it cannot tend to 

 twist it. 



4th. The tooth is not of the same form as Finlayson's, but it has, as 

 Finlayson's, a self-cleaning form. This will be understood from the figure 

 of it given above. It will be seen that the rise for the first five inches 

 is most gradual, and that any conchy earth or clods coming against it 

 will not be stopped by it and clog it, but will rise and tumble over, and 

 fall aside, and so pass by. This, with the height of the frame mentioned 

 in No. 1, and the distance between the teeth, spoken of in No. 2, hinders 

 any possibility of the machine being clogged in fast-land. 



5th. The machine is partly cast-iron and partly wrought ; and thus 

 while the liability of Biddell's to break is avoided, the advantage of 

 having the cheapness of cast-metal is partly ensured. The sections of the 

 teeth, given in a figure above, show that they are strong enough. Their 

 strength is increased by having an abutment on the frame, against 

 which they rest. The manner in which they are fixed to the frame is 

 also such as to increase their strength. Ihey are made slightly taper 

 at the place where they are keyed in, so that a blow of the hammer 

 makes them fit perfectly accurately to the frame. They are not fixed by 

 wedges, as the coulter of a plough, but by a key which passes through 

 the frame, through both the mortice and tenon, and thus holds them fast. 



6th. The mode in which it is raised out of the ground, and the plan 

 by which its depth is regulated, is an invention of Mr. Clyburn, of 

 Uley Works. The ease by which the operation is performed is greater, 

 and the complication of Biddell's scarifier is avoided, while the regularity 

 and parallelism of the motion of the frame-work, as it is raised or 

 lowered, is as perfect as in Scoular's or Kirkwood's. 



The hinder part of the machine is, as in Scoular's implement, raised 

 by increasing the inclination of the cranks which attach the hind-wheels 



