Thanks for citing (18 months ago) John Brinkley's paper on 'General Term.' Heard that Augustus De Morgan notified JH of deductions HW drew from Brinkley's theorems, extending them into permutations and combinations. Re-read JH's ['On the Development of Exponential Functions' (1816)]. Asks where to buy JH's Examples in Finite Differences [1820] for HW's great-nephew [Howard Elphinstone].