THE SIZE OF FARMS 



163 



and less important to him, until finally the point is reached 

 where the increase in the net profit is not sufficient to induce 

 the farmer to increase his activity. 



This can be illustrated by means of a diagram. In Fig. 9 

 the succeeding composite units of the agents are measured 



on the base line A X, and the net profit which the fanner re- 

 ceives for managing these units is represented by the area 

 between this line and the line BY, so that the area ABC'C, 

 for example, represents the net return from one of the composite 

 units. If the idea of a composite unit seems too abstract to 

 the reader, he may think of one of these units of the agents of 

 production as being one laborer and the amount of land and 

 equipment associated with him. That share of the net profit 

 per unit which is represented by the area lying below the curved 

 line PP' may be thought of as the amount which is required to 

 yield to the manager a pleasure in consumption of goods equal 

 to the pain of performing the work of management. Assuming 

 that he devotes exactly the same care to eacji unit, as he con- 

 tinues to increase the number of units the perpendicular dis- 

 tance between lines AX and BY will remain constant; but 

 a larger and larger proportion of the net profits of the succeed- 

 ing units will be required to counterbalance the pain or disutility 

 accompanying the added exertion required for the manage- 

 ment of such units, hence the curve PP' will gradually rise 

 until at some point it will cross the line BY, beyond which 

 point the pain of exertion exceeds the net profit to be secured. 



The curve PP', representing the increase in the pain cost, 

 may start high up the line AB and rise rapidly with a lazy 

 man, or it may start far below A, rise slowly and not reach 



