50. For interference with real property the measure of com-
pensation is the extent of the injury to the plaintiffs
right. If the injury is of a permanent nature, the meas-
ure is the diminution of the value of the property; other-
wise, the diminution in rental value. Whenever the
expense of making the injury good is less than the
diminution in value, such expense becomes the measure
of damages.^

Illustrations.
(a) The action is by a landlord of demised premises for injury
to his reversionary interests in pulling down a house. The measure
of damages is the diminution in the market value of the property.^

(fi) The action is for the destruction of a dam. The damages
include the value of the water privilege from the time of injury

' This results from the rule of avoidable consequences, discussed in
Chap. VI.
' Hosking v. Phillips, 3 Ex. 166.
198 ELEMENTS OP THE LAW OF DAMAGES.
