The present paper was undertaken on happening to peruse very lately Messrs. Gray, Smith, and Orchard's laborious and useful work, entitled Assurance and Annuity Tables, according to the Carlisle rate of Mortality, at 3 per Cent. In the introductory section of that work, when referring to the larger Tables V. and VI., containing the single and annual premiums for survivorship assurances, it is there very justly remarked, “Considering the frequency with which occasion arises for the functions here tabulated, and the tedious nature of the operations requisite when their values have to be formed from other tables, it may, at first sight, seem surprising that complete tables of them had not been formed long ere now; but the wonder will cease when it is farther considered that, until recently, there had been pointed out no other method of forming them than the tedious operation just referred to.