in anatomy. See Vol. I. p. 259.

Duple, among mathematicians, denotes the ratio of 2 to 1. Thus the ratio of 8 to 4 is duple, or as 2 to 1.

Sub-Duple ratio is just the reverse of the former, or as 1 to 2. Such is 4 to 8, or 6 to 12.