Ploughs and Ploughing. 



291 



makers have now adopted long handles on their chilled steel 

 implements for use in this country — even on wheel ploughs. 



Draught. 



The mechanical principles involved in the draught of the 

 ordinary plough control the arrangement and position of the 

 parts very much. The centre of draught — i.e., the point from 

 which the horses are in effect pulling — is situated behind the 

 heel of the share, about 2 inches above the sole-plate or level of 

 the bottom of the furrow, and 2 inches from the cheek-plate 

 (side-cap) or land side. Round this point the various forces or 

 resistances due to the turning furrow-slice, the cutting action 

 of the coulter, the wedge action of the share, and the pressure 

 of the solid ground on the land side, are balanced. It is not a 

 fixed point, but varies according to the kind of plough, the 

 •depth and width of the furrow-slice, and even varies as the 

 plough moves along when it meets an obstruction like a stone 

 or a stiff piece of soil, or when the ploughman swings the 

 handles one way or another. When the implement is properly 

 *' tempered," however, it always tends to right itself, so that 

 the line of draught will come back to the one point for that 

 particular set of the " irons " or special kind of plough. As 

 this " centre of resistance " is underground when the imple- 

 ment is at work it is impossible to attach the horses directly to 

 it, and therefore the arrangement of the beam or other frame- 

 work comes into play, whereby the horses can have a point of 

 •attachment above ground. For a swing plough the beam 

 should be as short as permissible, so that the horses shall 

 have as little leverage power as possible acting against the 

 leverage power of the man behind when holding the stilts ; 

 but in a wheel plough it may be longer — partly to give room 

 for the wheels and partly because these will take up and 

 carry any irregular draught on the part of the horses. The 

 line of draught passes from the shoulder-hooks on the horses' 

 hames to the " centre of resistance" above described in the body 

 •of the plough. It must pass through the point of attachment at 

 the end of the beam, so therefore there is here affixed a bridle, 

 head, muzzle, hake or clevis (as it is variously called), whereby 

 •this point may be moved up or down or sideways by means of 



