FACTORS OF AGRICULTURAL PRODUCTION 221 



plowed with three horses, and so on, the addition made by each 

 horse as others are added being | of an acre, \ of an acre, | of 

 an acre, and \ of an acre. 



Reducing these figures to the following diagram, let the work 

 done with one horse be represented by the rectangle I, that 

 done with two horses by the sum of the rectangles I and 2, 

 thai done with three horses by the sum of the rectangles I, 2, 

 and 3, etc. The rectangle 3 then represents the additional 



work done with the third horse over and above what could be 

 done with two, etc ; that is, rectangle 3 is the effective work 

 done by the third horse, and measures his value in the team. 

 The value of the additional horses thus dwindles away until the 

 rectangle 8 represents the effective value of the eighth horse. 

 If the value of a quarter of an acre of plowing (rectangle 8) is, 

 under the circumstances of time and place, greater than the cost 

 per day of one horse, then it pays to use eight horses ; otherwise 

 not. Find the rectangle in this diagram which represents suffi- 

 cient plowing to have the value which approximates most closely 

 to the daily cost of one horse (including, of course, all the items 



