130 MECHANICS. 



that "by shortening the traces or draught chain, or giving 

 them a little more length, it would run like another plow. 

 Wlien a plow is adjusted to run just riglit, as the point 

 wears off it is necessary many times to give a little more 

 length to the draught chains, or to adjust it with the 

 clevis to run a little deeper. It is sometimes impossible 

 to adjust a plow to run just right with the style of clevis 

 which is on the end of the beam. The arrangement ought 

 always to be such that the draught can be adjusted half 

 an inch at a time, either up or down, or to the right or 

 left. Then if the beam of the plow stands as it should, so 

 that the most correct line of draught will cut the end of 

 the beam^ it can be most correctly adjusted in a few 

 seconds. 



" To make a plow run deeper, raise the connecting point 

 at the end of the beam one or more notches higher in the 

 clevis ; or lengthen the draught chains. To make it run 

 more shallow, lower the draught a notch or more in the 

 clevis ; ov shorten the draught chains ; or, which should 

 never be done, shorten the back-bands or hip-straps of the 

 harness. To make a plow take a wider furrow-slice, carry 

 the connecting point one or more notches in the clevis to 

 the right hand. A notch or two to the left hand will 

 make a plow cut a narrower furrow-slice. Or, which is 

 seldom allowable, a plow may be made to run more shal- 

 low by putting the gauge-wheel lower, so as to raise the 

 end of the beam. And a plow may be made to cut a nar- 

 rower furrow-slice by carrying the handles to the left 

 hand, or wider by carrying and holding them to the right, 

 beyond an erect position ; neither of which is allowable, 

 except for a temporary purpose." 



FAST AND SLOW PLOAVING. 



It has already been shown in the chapter on Friction, 

 that the resistance is scarcely increased by velocity, when 

 one body slides over another. The same rule, nearly, ap- 



