DEMAND 
89 
articles or services, total utility means the 
loss of satisfaction which would be sustained by 
the complete withdrawal of that commodity 
or service, while the marginal utility means 
the addition made to our total satisfaction 
by the acquisition of the last increment of 
the commodity or -service. The diminution 
spoken of in the law of diminishing utility 
refers to marginal and not to total utilities; 
though total utilities may themselves contract 
when people are encumbered with things of 
which they want no more, in which case 
marginal utilities are said to have become 
negative. 
We are now in a position fully to grasp 
the conception of demand. We are said to 
demand a thing when we are prepared to offer 
something of value for it. When the offer 
is made in terms of money the offer is said to 
be a demand price. Now it will be apparent 
that a person will buy more of a thing when 
the price falls. In ordinary circumstances, 
since the marginal utility of a thing drops 
when a person gets more and more of it, 
price must be diminished if he is to be induced 
to purchase larger quantities. Thus, were the 
price of tea 18s. a pound, I would buy only 
one pound a year, say ; but if the price were