PRESIDENTIAL ADDRESS. 541 
facts: (1) that corn can be grown in some places with a less expenditure of 
capital and labour than in others; and (2) that the quantity of the more 
favourable land is limited. Whence it follows that growers will first have 
recourse to the most fertile land; afterwards to that which is less fertile. 
If we were acquainted exactly with the economics of corn-growing we could 
represent this state of things in any country at any given time by a curve like a 
barograph. 
Along the line OX (fig. 3), instead of the progressive days of the week, we 
should mark off successive quantities of corn, and the vertical height of the curve 
above any given quantity would represent the price per quarter of production 
Y, Money 
©, 
ie 
O X 
Fie. 4. 
of that part which was produced at greatest expense. Thus, the cost of pro- 
duction of the first and most easily grown quarter would be, say 18s., of the next 
18s. 1d., and so on. And it would be evident that the total cost of the whole 
of the wheat grown would be obtained by adding all these prices together— 
that is to say, by the area of the curve OMBA; for an area is but the sum 
of all its constituent parallel lines, just as the total of a bill for goods is an 
addition of all its items. 
Let us now dismiss this corn-growing graph from our minds and turn to 
another side of the question. Let us consider the various prices which con- 
sumers would give for various quantities of corn if they could get these and no 
more. I do not mean the market prices of the quantities, but what might be 
called the famine prices, which they would give rather than not have the corn. 
If we draw a corn-consumers’ graph it will obviously be a descending curve, 
for the more they can get the less they will value successive portions. In fact, 
¥ 
‘Oh M X 
Fic. 5. 
if the supply of corn were unlimited the surplus would be used first to feed 
animals, then to consume as fuel, then as manure, and at last have to be 
destroyed as a nuisance. 
The curve would be of the form shown in fig. 4. 
The contemplation of these curves of corn will no doubt suggest the ques- 
tion whether if we had them both we could tell what the market price would be. 
For it seems obvious that if we know all the conditions, both of demand and 
supply, we ought to be able to foretell the market price. This is the case 
and can be easily done. All that is necessary is to superpose the curves, as is 
done in fig. 5. 
We then see at once that PM must represent the market price of corn per 
