In J.I.A. Vol. XLIV, pp. 261–83., Lidstone developed, as far as terms involving μ. and δ, the adjustments required in a valuation in order to allow for premiums payable more frequently than once a year. Practical working approximations to these adjustments were also given, and were summarized in a table at the end of the paper, which for convenience of reference is here reproduced (the symbol OS is used to denote the instalments of premium falling due between the valuation date and the next ensuing policy anniversary).