The questions depend upon the true construction of s. 59 of the Act. That section is one of a group of sections comprising ss. 54 to 62 both inclusive, which deal with the topic of depreciation. Sections 54 to 58 are directed to making depreciation, at rates provided for, an allowable deduction in respect of property being "plant" (an expression defined to include certain items of property described by reference to their use in relation to a purpose of producing assessable income), or being articles owned by a taxpayer and used by him during the year of income for the purpose of producing assessable income. As a corollary, s. 59 deals with the situation which arises where at any time in a year of income property in respect of which depreciation has been allowed or is allowable is disposed of, lost or destroyed. The section requires a comparison to be made between the depreciated value of such property (in effect, as s. 62 provides, its cost to the taxpayer less the total amount of depreciation allowed or allowable to the taxpayer in respect of it for any anterior period), and any consideration receivable in respect of the disposal, loss or destruction. If the consideration receivable is less than the depreciated value, the deficiency is made, by sub-s. (1) of s. 59, an allowable deduction. If, on the other hand, the consideration receivable exceeds the depreciated value, the excess, to the extent of the sum of the amounts allowed or allowable in assessments for income tax in respect of depreciation, is included, by sub-s. (2), in the taxpayer's assessable income. For the purposes of these provisions, sub-s. (3) enacts a definition of the expression "the consideration receivable in respect of the disposal, loss or destruction". It means - (a) in the case of a sale of the property - the sale price less the expenses of the sale of the property; (b) in the case of loss or destruction of the property - the amount or value received or receivable under a policy of insurance or otherwise in respect of the loss or destruction; (c) in the case where the property is sold with other assets and no separate value is allocated to the property - the amount determined by the commissioner; (d) in the case where property is disposed of otherwise than by sale - the value, if any, of the property at the date of disposal.