210 POWER AND THE PLOW 



The point of hitch is lower on a plow than on a wagon. Fre- 

 quently a strap is provided at the saddle or rump to hold up 

 the traces while the team stands. When the same team and 

 harness are used on the plow an angle is formed at the trace. 

 Sanborn found the downward pull at this point to equal 50 

 Ibs., or one third the pulling power of an average 1200 to 1500 

 Ib. horse. The angle was not as great as he had frequently 

 observed, but even then a third of the animal's power was being 

 used to gall and annoy it instead of being applied to the work 

 in hand. 



The New York Agricultural Society's estimate of the divi- 

 sion of the draft explains the enormous difference in draft 

 between a sharp share and a dull one, also why it is possible 

 to add the weight of a heavy plow frame and a driver to the 

 load of the horses, yet not increase the draft. The friction of 

 the sole, estimated at 35 per cent., is transferred almost entirely 

 to wheels in the sulky plow. The landside is made much 

 shorter, and the heel of the latter is usually carried a fraction 

 of an inch from both the bottom and side of the furrow by 

 means of a staggered wheel. The lifting of the soil is borne 

 by the larger wheels and frame, while the relatively small 

 moldboard friction remains constant. Sanborn shows only 

 .19 Ib. per inch, or 3.3 per cent, difference hi draft in favor of 

 walking over sulky plows, averaging three tests of each, but 

 observes that the draft of sulky plows increased on the hills. 

 Considering amount and quality of work, the difference in 

 draft is negligible. In fact, an unskilled plowman will even 

 cause greater draft in a walking plow by constantly disturbing 

 its adjustment. The influence of the operator's efforts to help 

 the adjustment was seen in one trial in which different plowmen 

 in successive furrows varied the draft from 5.19 to 4.45 and 

 5.61 Ibs. per inch, respectively, while another on several trials 

 ranged from 5.25 Ibs. to 6.15 Ibs. A small truck or gauge 

 wheel under the beam of the plow should, theoretically, in- 

 crease the draft by adding friction and by frequently disturb- 



