78 VALUATION, DEPRECIATION AND THE RATE-BASE
down. Under such a rule all relation between the capital legitimately
 invested and the cost of reproduction may be lost. In
a private enterprise the former and not the latter would be used
as the guide in determining what the earnings should be. But
the cost of reproduction is generally held to deserve special consideration
 when the “fair value,” required by the courts, is to
be appraised and it is frequently accepted as the starting point.
When the courts shall have accepted the view that “ fair value
is not the proper starting point, then the importance of close
estimates of the cost of reproduction, which includes both depreciation
 and appreciation, will fall away.