Capital gains tax calculation revised to apply scaled average income- and super-tax rates with minimum and low-income exemptions. The amendment substitutes sub-clause (ii) to require that the amount of income-tax and super-tax on that part of net capital gains (other than short-term assets) exceeding the threshold be computed at three-fourths of the average income- and super-tax rates for gains from buildings or lands, and at one-half of those average rates for other assets; average rates are computed as for the prior sub-clause. A proviso fixes a minimum tax floor as a proportion of net capital gains where the computed amount is lower, and another proviso exempts small total incomes.