in the theory of value and prices. 



O'/ 



ratio 07/OR so that by getting it at less than he was willing to pay, 

 he has gained the element 35 measured in corn. His gain is maxi- 

 mum when he purchases such a quantity that its final utility equals 

 its price. 



Fig. 39 applies to "producer's rent" or "gain," substituting 

 *' sale " for " purchase "; " sell " for " buy." 



To express the gain in money the area M26 must be multiplied by 

 the price. On each cistern construct the curve 62 (fig. 38) and con- 

 sider the area RA26 to move front and back one unit (say one inch) 

 so as to trace a volume (fig. 40) adjacent to the front cistern and 



40. 



again to move p inches further back so as to trace a volume adjacent 

 to the back cistern. 



The front volume gives again the total utility measured in com- 

 modity. The back volume gives the total utility measured in money. 

 That is the whole back cistern and its adjacent volume represent the 

 money which if the individual paid he would neither gain nor lose, 

 provided his marginal valuation of it is unchanged by the operation. 

 The cistern portion is the money he actually pays and the outside 

 volume 7, 10, 12, 9, 8, 11 is his "gain." Likewise for the producer. 



III. GAIN A MAXIMUM. 



In the case of a single individual distributing a fixed income over 

 various commodities under fixed prices the distribution actually 



Trans. Conn. Acad., Vol. IX. 7 July, 1892. 



