Another and apparently opposed school has tended in the same direction. The more accurate study of the variations of utility, which forms the common starting-point of the researches of Jevons, Menger, and Walras, has among its other important effects given a new mode of measuring the pressure of taxation. Final or marginal utility becomes the measure of sacrifice, and if, as is plain, the utility of a shilling is more to the possessor of an income of £100 than it is to one of £1,000, it does not follow that it is exactly ten times as great. The assumption that equal percentages of income are of equal utility is a rough 'first approximation,' admissible, perhaps, in the earlier stages of inquiry, but certain to give place to the more accurate results of later investigation. It is noticeable that Sax and Wieser, who represent the financial studies of the Austrian school, have both declared for progressive taxation.