Dean's interest and equation exponents : a system of exponents, governed by the principles of decimal notation, by means of which the correct interest of any sum, at any rate per cent., for any given time, is ascertained almost at a glance : with a special adaptation to the purposes of equation, constituting the same : the most rapid and convenient method known of averaging accounts, based on the rate of 10 per cent. per annum, of 360 days /