Sec. 8] EARNINGS AND INCOME 245

dwelling itself instead of selling some property distinct
from the dwelling. Or again, he may make an arrangement
 at the outset to pay for the house in installments.

All of these methods of maintaining more or less regularity
 of income merely shift the burden of an unusual
expense from one person to another. The first method,
by which the purchaser of the house raises the necessary
money by selling other property, shifts to the buyer of
that property an expense equal to that which he himself
seeks, for the time, to avoid. The second method, that of
mortgage, presupposes a money lender who is ready to supply
 the necessary funds. The money lender is in this case
the one who, for the time, shoulders the burden. The
third method, payment by installment, implies that the
builder (or some other party) advances the cost of the dwelling.
 In other words, the person who attempts to smooth
out his own income does so by throwing his irregularities
on some one else, usually a banker or broker.
To society as a whole such purely shifting devices are
inapplicable, for society can find no outside party on whom
to shift the fluctuations. There is, however, a method by
which society’s income may be more or less standardized.
This is by assorting and combining the various instruments
 of capital wealth so that the various income
streams may mutually compensate. For instance, if a
community owns iron mines, it has a form of property
which, for a time, probably yields more than the standard
income. By the nature of the case, every bucketful of ore
reduces the amount which the mine can yield in future.
The mine is, in fact, a sort of terminable annuity. After it
is exhausted there will be no further returns. The capitalvalue
 of the mine will therefore continually decrease. On
the other hand, forest land which is covered with young
saplings will not begin to yield much income for many
years. The income from this capital is therefore tempo-