An index to interest : containing, I. the largest tables of simple interest that have yet been made publick ... II. a table of discount ... III. two tables shewing ... the present worth of annuities ... IV. an easie table for the valuation of any number of years lapsed in a church or college-lease of land ... V. tables of the amount and present worth of any sum of money, and of annuities to 61 years ... : also the full use of all the tables ... : together with a new invented circle for the easie finding the number of days contain'd between any two in the year ... /