tion may have in such properties, either through a payment originally made for acquirement thereof or for improvements made upon the property, to be accounted for in accordance with regulations governing depreciation allowances and disposition of capital assets. 105. In respect to properties of the character in question which may be acquired by a corporation after January 1, 1909, a deduction will be allowed only as to depreciation arising from exhaustion based on original cost; no exclusion from gross income can be made for unearned increment, as profit arising in sale of such capital assets applies wholly to the period subsequent to January 1, 1909. Modifications of note in item No. 99, and items 100, 101, and 103 of Treas. Decis. (1742), relative to claims for unearned increment in returns of annual net income of mining corporations are stated in 24 Treas. Decis. (1833). No. 99. The note is amended so that it shall read: NOTE. Values, as aforesaid, should not be estimated on the basis of the assumed salable value of the output under current operative conditions, less the actual cost of production, because, as hereinbefore stated, the selling price under such conditions comprehends a profit both for carrying the investment in coals, etc., improvements and working capital, and for conducting operations in respect of production and disposal of product. The value to be determined as stated must be on the basis of the salable value en bloc of the entire deposit of minerals and mineralized property owned, exclusive of improvements and development work, if the same were disposed of in that form. No. 100 is amended to read: The unit value as of January 1, 1909, ascertained as above outlined, would indicate the value to be attached at that date to the capital assets disposed of during any calendar year succeeding. The amount claimed as a deduction from gross income on account of unearned increment shall be shown separately in the deductions from gross income in the return of annual net income. No. 101 is amended to read: The precise detailed manner in which the estimate of value of minerals, etc., as at January 1, 1909, shall be formed, must naturally be determined by each corporation interested. Every corporation claiming and making a deduction for unearned increment, as provided in section 100 preceding, shall maintain an official book record of the properties owned by it in connection with which unearned increment is claimed, and which record shall show the general ledger or general balance sheet value thereof, together with the estimated amount of appreciated value in such properties in excess of general balance sheet values, as of January 1, 1909, together with all evidence and information on basis of which such appreciated value was formed. This estimate must be formed on the lines and basis indicated in the "note," section 99, namely, the salable value of the entire deposit considered en bloc. This record should also present clearly and fully the transactions during each year in respect of quantities of minerals disposed of and for which deductions are made respectively for depreciation and unearned increment, together with the amount thereof. No deduction for unearned increment will be allowed unless the aforesaid record is kept, nor unless the evidence as to the estimates of quantity of minerals in deposit and the valuation thereof are accepted by the department. Values determined and recorded as of January 1, 1909, as aforesaid, should be used in the compilation of all subsequent years' excise tax returns. In case it subsequently develops the property possesses a greater quantity of mineral, etc., reserve than was in the aggregate estimated as of January 1, 1909, only such an amount of aggregate value can be assigned to such excess mineral tonnage as of January 1, 1909, as it was at said date estimated by the company attached to the property and was not assigned by it, as herein before provided, to the special tonnage in the property. No. 103 is amended to read: As the amount to be deducted for depletion of deposits (Regulation No. 101) is to be formed on basis of the estimated reserve of minerals, etc., it follows that if it develops such estimate is understated, the cost investment and estimated unearned increment in the capital asset may be wholly extinguished before all mineral reserves are removed. When this is reached, further deductions for exhaustion of minerals should be discontinued. Regulation to govern the ascertainment of the rate of depletion of deposits and the return of cash investment to corporations with respect to natural gas-producing properties may be found in 22 Treas. Decis. (1754). See (1675). Regulation to govern the ascertainment of the rate of depletion of deposits and the return of cash investment to corporations with respect to petroleum-producing properties is given in 22 Treas. Decis. (1755). In United States v. Nipissing Mines Co., 202 Fed. Rep. 803, it was held that a mining corporation engaged in extracting ore from its mines was entitled to an allowance for depreciation equal to the value in place of the ore extracted and disposed of during the year. (d) When the assessment shall be made, as provided in this section, the returns, together with any corrections thereof which may have been made by the commissioner, shall be filed in the office of the Commissioner of Internal Revenue and shall constitute public records and be open to inspection as such: Provided, that any and all such returns shall be open to inspection only upon the order of the President, under rules and regulations to be prescribed by the Secretary of the Treasury and approved by the President: Provided further, that the proper officers of any State imposing a general income tax may, upon the request of the governor thereof, have access to said returns or to an abstract thereof, showing the name and income of each such corporation, joint-stock company, association or insurance company, |