(_e_) A reasonable profit on the fair value of the property. An investigation of non-physical values should then include an analysis of operating expenses, to determine that additions and betterments to property are not included therein. The general practice of corporations in the past has been to ignore any reserve to cover depreciation and obsolescence. If, at the beginning of operations of any property, such a sum should be annually set aside out of earnings as should, when invested as a sinking fund, maintain the integrity of the investment, then this amortization fund at any period, plus the depreciated value of the physical property, should equal the amount of the total capital actually invested in the property. In most cases this has not been done, and the Supreme Court in the Knoxville Water Case holds that, by reason of the failure to create such a fund, whether due to carelessness, excessive dividends, or other cause, the company must lose the amount of capital represented by the depreciation that has taken place. In making a computation of intangible values, it is certainly proper to consider the income account as averaged over a period of years, to avoid violent fluctuations of gross or net earnings, and a depreciation reserve should be determined for such years, as it cannot be claimed that, unless such an amortization fund is earned, in addition to other operating expenses and taxes, there is any non-physical value. Professor Adams covered the depreciation in the Michigan work in the 4% annuity which was deducted before non-physical values were computed. The writer is inclined to go a step farther than Professor Adams, and hold that, before any intangible values can be attached to the property, it should earn not only all operating expenses, taxes, and reserve for depreciation, but also interest on the actual investment equivalent to the return that would be had were the money invested in a non-taxable bond, say 4%, and that any earnings in excess of such a sum might be termed properly "earnings on franchise," or intangible values. On this basis, then, a rule would be formulated, being that of Professor Adams, with some modifications: _1._—Deduct from gross earnings from operation the aggregate of operating expenses, including in operating expenses an annual sinking fund to amortize the depreciation and obsolescence, and the remainder may be termed "income from operation." _2._—To this income from operation add income from investment, giving "total income," which represents the amount at the disposal of the corporation for the support of its capital and for the determination of its annual surplus.