76 POLITICAL ECONOMY 



THE GRAPHIC REPRESENTATION OF THE LAWS 

 OF SUPPLY AND DEMAND, AND THEIR 

 APPLICATION TO LABOUR. 1 



I. 



GRAPHIC REPRESENTATION OF THE LAWS OF SUPPLY AND 

 DEMAND. 



RECENT discussions on the laws determining the price of commo- 

 dities seem to show that these laws are neither so well under- 

 stood nor so clearly expressed in the writings of economists as is 

 sometimes supposed. Men are too much in the habit of speak- 

 ing of laws of political economy, without attaching to the word 

 law the same rigid meaning which it bears in physical sciences. 

 There are, however, some truths concerning the subjects treated 

 by the economist which do deserve the name of laws, and 

 admit of being stated as accurately, and defined in the same 

 manner, as any mathematical laws affecting quantities of any 

 description. 



The following essay is an attempt to state in this rigorous 

 manner some propositions concerning the market price of com- 

 modities, using what is known as the graphic method of curves 

 to illustrate the laws and propositions as they arise. 



First, I will consider what determines the price of a com- 

 modity at a given time in a given market, and it is unfortunately 

 necessary for this purpose to define the sense in which some 

 words will be used. 



The whole supply of an article will be taken to mean the 

 whole quantity of the article for sale there and then. Supply 

 is in this sense mensurable, and can be expressed in tons, 



1 From Recess Studies. Edited by Sir Alexander Grant. Edinburgh, 1870. 



