An essay to ascertain the value of leases and annuities for years and lives : and to estimate the chances of the duration of lives : wherein are many observations on bills of mortality, on the state of the coin, the interest of money ... also rules are therein given for reducing leases for years or lives to clear annuities ... a method likewise is shewn, of calculating to what number of years any given life or lives, on an even chance, may probably extend ... to which are added, in the appendix, tables adapted to these several purposes, and to most cases which may arise on the value of estates of this kind /