The Revenue Act of 1936 provides that in computing net income from oil and gas properties there shall be allowed as a deduction from gross income a reasonable allowance for depletion, according to the peculiar conditions in each case. The allowance is made under regulations prescribed by the Commissioner of Internal Revenue.

The first problem is to fix the amount the taxpayer is entitled to recover before he is considered as earning income which is not in essence a mere return of his capital investment. The difficulty of clearly defining the difference between a return of capital and of income has often been discussed.