182 Report on Trials of Flows. 



the coulter and its adjustment. It should be made of iron, faced 

 with steel, and of sufficient bulk to stand firmly in the position 

 in which it is set for its work; not to bend either to the right hand 

 or to the left. The most approved 

 English coulters are about two and 

 a half inches wide, and formed by 

 the meeting of two curves, as in 

 Fig. 89 . The land side of the 

 coulter should be flat, and the 

 opposite side a gradual taper from 

 the edge to the back. The thick- 

 ness must be determined by the ^f'^- ^2. 

 strength of the work it has to perform. American coulters are 

 generally made either straight edged, as in Fig. 87, or slightly 

 curved backward from the point. When secured, as shown in 

 Fig. 89, it is kneed inward, so as to adjust it to the plane of the 

 land side. 



Having now considered the various forms of the coulter, we 

 pass on to a consideration of its function and its adjustment. 



Mr. Stephens has asserted that the force required to draw a 

 coulter seven inches deep in the earth requires no more power 

 than it does to draw a plow making a furrow seven inches deep 

 and ten inches wide, without a coulter. This experiment, we 

 believe, stands alone, unsupported by the testimony of any other 

 observer. We had desired to verify it at Utica, with every pre- 

 caution to insure accuracy, but were prevented from doing so by 

 the unexpected and untimely removal of the dynamometer from 

 thence. 



The subject being one of such great importance, we give -Mr. 

 Stephens' statements in his own words: 



" On a subject which has of late attracted considerable atten- 

 tion, I was desirous of obtaining information from experiments 

 alone on the actual implement; and, to attain this more fully, I 

 determined on analyzing the resistance as far as possible. With 

 this view, a plow was prepared whose coulter was descended 

 seven inches below the line of the sole, and fitted to stand at any 

 required angle. This plow, with its sole upon the surface of a 

 two-year old lea, and the coulter alone in the so^7, the bridle 

 having been adjusted to make it swim without any undue tendency, 

 the force required to draw this experimental instrument, as indi- 

 cated ])y the dyii!inionieter, was twenty-six imperial stones (350 



