1815. Living individual 1 1785. His father and mother 2 1755. Their fathers and mothers 4 1725. ” ” 8 1695. ” ” 16 1665. ” ” 32 1635. ” ” 64 1605. ” ” 128 1575. ” ” 256 1545. ” ” 512 1515. ” ” 1,024 1485. ” ” 2,048 1455. ” ” 4,096 1425. ” ” 8,192 1395. ” ” 16,384 1365. ” ” 32,768 1335. ” ” 65,536 1305. ” ” 131,072 1275. ” ” 262,144 1245. ” ” 524,288 1215. ” ” 1,048,576 1185. ” ” 2,097,152 1155. ” ” 4,194,304 1125. ” ” 8,388,608 That is to say, if there have been a regular co-mixture of marriages, every individual of the living race must of necessity be descended from parents who lived in Britain in 1125. Some districts or clans may require a longer period for the co-mixture, and different circumstances may cut off some families, and expand others; but, in general, the lines of families would cross each other, and become interwoven, _like the lines of lattice-work_. A single intermixture, however remote, would unite all the subsequent branches in common ancestry, rendering the contemporaries of every nation members of one expanded family, after the lapse of an ascertainable number of generations.”[33] --------------------- Footnote 31: Dr. Johnson. Footnote 32: _The Doctor._ Footnote 33: Sir Richard Phillips’s _Morning’s Walk from London to Kew_. ---------------------------- AVERAGE DURATION OF LIFE.