Page:William Blackstone, Commentaries on the Laws of England (3rd ed, 1768, vol II).djvu/220

 206 be the quadruple of thoe in the degree which immediately precedes it. For, ince each couple of ancetors has two decendants, who encreae in a duplicate ratio, it will follow that the ratio, in which all the decendants encreae downwards, mut be double to that in which the ancetors encreae upwards: but we have een that the ancetors encreae in a duplicate ratio: therefore the decendants mut encreae in a double duplicate, that is, in a quadruple, ratio.

This calculation may alo be formed by a more compendious proces, viz. by quaring the couples, or half the number, of ancetors at any given degree; which will furnih us with the number of kindred we have in the ame degree, at equal ditance with ourelves from the common tock, beides thoe at unequal ditances. Thus, in the tenth lineal degree, the number of ancetors is 1024; it's half, or the couples, amount to 512; the number of kindred in the tenth collateral degree amounts therefore to 262144, or the quare of 512. And if we will be at the trouble to recollect the tate of the everal families within our own knowlege, and oberve how far they agree with this account; that is, whether, on an average, every man has not one brother or iter, four firt couins, ixteen econd couins, and o on; we hall find that the preent calculation is very far from being overcharged. method of computing thee degrees in the canon law, which our law has adopted , is as follows. We begin at the common ancetor, and reckon downwards; and in whatoever degree the two perons, or the mot remote of them, is ditant Rh