Supplementary Plow Trials. 



267 



The average difference of draught for each half inch of depth 

 is 45.5 pounds, or 91 pounds to each inch. The accuracy of this 

 average is somewhat impaired by the fact that there is a difference 

 in the breadth of the furrows, the extremes being 2| inches apart. 



We next began a series of experiments to determine the rates 

 of draught to depth with Holbrook's Plow No. 69, with a coulter 

 and sod mould-board: 





C 

 3 

 O 



a 



3 



REMARKS. 



15 



16 

 17 



18 

 19 

 20 

 21 



22 

 23 

 24 

 25 

 26 

 27 



28 

 29 



30 

 31 



32 

 33 



34 

 35 

 36 

 37 



10 

 10 

 10 

 10 



10^ 

 lOi 

 11 

 11 



16 

 16 

 18 

 18 

 18 

 18 

 18 

 18 

 18 

 18 



18 

 18 



18 

 18 

 18 

 18 



18 

 18 

 18 



*118 

 *107 

 * 99 

 647 

 594 

 540 

 551 

 558 

 618 

 626 

 603 

 603 

 578 



744 

 791 



800 

 871 

 755 

 734 



876 

 1,215 



976 

 1,080 



Average of fifteenth, sixteenth and seventeenth experi- 

 ments, 108 pounds. 



Average of eighteenth and nineteenth experiments, 

 621 pounds. 



Average of twentieth and twenty-first experiments, 

 5455 pounds. 



Average of twenty-second and twenty-third experi- 

 ments, 588 pounds. 



Average of twenty-fourth, twenty-fifth, twenty-sixth 

 and twenty-seventh experiments, 601 pounds. 



A-verage of twenty-eighth and twenty-ninth experi- 

 ments, 767 pounds. In the twenty-ninth, the 

 coulter obstructed by quack roots. 



In the thirtieth experiment the coulter obstructed by 

 hardback roots; in the thirty-first the coulter 

 obstructed by quack and hardback roots. Average 

 of thirtieth, thirty-first, thirty-second and thirty- 

 third experiments, 790 pounds. 



Average of thirty-fourth, thirty-fifth, thirty-sixth, 

 and thirty-seventh experiments, 1,012 pounds. 

 This great draught was caused by the blunt shank 

 and knee of the coulter running into the sod 

 at this depth. They are retained in the table as 

 instructive illustrations of the effect of a blunt 

 coulter, but are rejected in making up the averages, 

 which are taken from the eighteenth to the thirty- 

 third experiments, both inclusive. 



* Surface draught. 



Average depth from eighteenth to thirty-third experiment.s, 

 7.94 inches; average width, 17.80 inches; average draught, 663 

 pounds; average prism, 141.33 square inches. Average prism 

 from twenty-fourth to twenty-seventh experiments, 144 square 

 inches; average draught, 601 pounds. 



