DEMAND 
59 
good enough to get employment is called the 
marginal workman or the workman of marginal 
quality. Also the employer in an industry 
whose capacity only just attains the level 
which enables him to make a living in the 
industry is the employer of marginal quality. 
It is exceedingly important that the distinc 
tion between these two uses of marginal should 
be firmly grasped. 
We are now adequately equipped to define 
wealth and value. Broadly understood all 
that people want is wealth. But sometimes 
the conception is narrowed to exclude things 
that are accessible to all and unlimited in 
quantity such as air ; and sometimes in 
addition the qualification is introduced that 
desirable things to be wealth must have 
been produced by labour. Value may mean 
value in use or value in exchange. By the 
former is meant the utility, as above defined, 
of things that are wanted ; and by the latter 
is meant the quantity of other things that 
the thing in question will exchange for. The 
value in exchange of an article or service is 
evidently dependent upon its marginal utility 
to would-be purchasers and the marginal 
utilities of the things offered for it. When 
what is offered is money, value in exchange is