APPENDIX

201

where QR, parallel to Oz, cuts D,d,, some supplies of the
second commodity will be demanded. In the former case,
when satisfactions had to be as great as PN to be worth
securing, only the first commodity could afford them. In
the latter case,
when utilities
measured by
QM are worth
securing,  supplies
 measured
by OM of the
first and OL of
the second commodity
 are
desired. To
divert the means
devoted to procuring
 the supply
 OL of the
second commodity,
 and extend
 the amount
of the first
secured, would be to secure utilities, whose measure is less
than QM, by the sacrifice of some whose measure is greater
than RL, that is, greater than QM.
The fact that there are very many different kinds of
satisfaction which can be procured easily accounts for the
fact that there are few lines of consumption which are pushed
to the point of absolute satiety. There is no need to press
on along one demand curve Dd, to the point where it cuts
Ox so long as there is some other demand curve, relating to
commodities procurable and appreciated, some part of which
lies above Oz, and the desires corresponding to which are
aot yet satisfied.
Incidentally it may be noted that, if means be distributed
with strict regard to the utilities secured, the level of
marginal utility procured in every line of consumption will
be the same. Each commodity will be enjoyed in such
quantity as to have a marginal utility not less than that of
each of the other commodities secured by the same person.
Returning to the consideration of Fig. (ii), we may give
expression to the conception of elasticity of demand dealt
with on pn. 26. The line PQ, when P, Q, approach each other