waterman's dynamometer, 105 



this wheel by an arrangement similar to that already de- 

 scribed for registering the distance. 



This explanation shows the principle of the self-regis- 

 tering attachment, but in one respect it must be varied in 

 order to be entirely accurate. The ratchet wheel must 

 necessarily permit some play of the click or pawl, which 

 would soon lead to serious error. This is wholly prevent- 

 ed by facing the wheel with India rubber, and causing 

 the pawls to press this India rubber surface. * 



It will be observed that a movement of this wheel is 

 made at every revolution of the band-wheel, or once in 

 every yard ; and in traveling a hundred yards, a hundred 

 such movements are made. Every one of these may be 

 different in amount from the others, yet the whole sum 

 will be accurately measured. 



It is absolutely essential that every part be finished with 

 perfect workmanship, so that there may be no play or 

 rattling of the teeth, producing loss of motion. Its 

 measurements have been entirely satisfactory, although its 

 records must necessarily vary with the condition of the 

 cutting edge of plows, with the running order of mow- 

 ing machines, the temper or sharpness of the knives, and 

 the skill of the manager or driver. 



A more general use of the dynamometer would doubt- 

 less result in important advantage to farmers as well as 

 plow-makers. The trials which have been made, both in 

 this country and in Europe, have proved that a great dif 

 ference exists in plows, as to ease of draught, some 

 plows requiring a force more than fifty per cent greater 

 than others, to turn a furrow of equal width and depth. 

 Hence the farmer who employs the plow which runs most 

 freely may accomplish as much by the use of two horses, 

 as another can do by using one of hard draught by em- 

 ploying three horses. 



R* 



