¶2The foregoing facts are substantially all that are contained in the record. The Commissioner traversed the depletion deduction in its entirety and thus placed upon the petitioner the burden of proving all the factors of depletion. That the facts are inadequate for this is manifest.
¶3We have made no finding of value on March 1, 1913, because the bare expressions of opinion of the petitioner’s witnesses were not in our opinion sufficiently well founded to tend to establish a value. The witnesses merely said they thought the tracts were worth somewhere from $75 to $100 an acre. Such an opinion can have weight only if there is reason to believe that it is held by one whose general and specific knowledge and whose ability to form an opinion entitle him to speak with some measure of authority.
¶4Although both counsel in brief submit computations of depletion, such computations include factors which are not in evidence — such, for example, as the tonnage of coal mined in the taxable years. Were these facts either proven or stipulated we could consider them; but their mere statement in brief must be disregarded.
¶5Judgment for the Oommissio'ner.