History of the Plow. 



71 



lar, after passing which the gratlual overhanging of the mould- 

 board pushes the furrow slice (supposing it to rest on its lower 

 edge as a hinge) beyond the centre of gravity, and at length 

 completely snl)verts it; or, in farmers' language, lays it upon its 

 l)ack. The angle which tJie .stright line should form with the sole 

 of the plow is another material point to be discovered b}^ expei'i- 

 ments. 



" In adjusting this mould-l)oard to the plow, another point is 

 to be determined — the extent of the angle which the essential 

 stright line should form with the bar of the share or land side 

 of the plow. The smaller this angle the less the resistance at 

 entering the earth; but if the angle were to be very small,, then 

 the plow must have great length to obtain a proper breadth of 

 furrow; and such great length would proportionally increase the 

 quantity of friction. Hence the conclusion, that keeping both 

 these points in view, repeated experiments must decide where 

 lies the just medium of breadth, of angle, and length of mould- 

 board." 



The lines running from the front of the plow towards the back 

 are now usually transverse lines, but Mr. Pickering evidently 

 applies this term to the lines running from the sole to the top of 

 the plow. 



The next patent granted was to Hezekiah Harris, of Kentucky, 



J^fff. 62. 

 on the 24th of February, 1808, of which no record remains in the 

 patent office, and of which we can learn nothing whatever. The 



next M-;is to Kicliard B. Chonowotli, of Maryland, a drawing of 



