Convert from palm [US, Roman major] to pouce

Unit Definition (palm [US, Roman major])
A palm, when used as a unit of length, is usually four digits or three inches, i.e. 7.62 cm (for the international inch). The width of an adult human male palm is indeed about 10 centimetres.In English this unit has mostly fallen out of use, as do others based on the human arm: digit (¼ palm), finger (7/24 palm), hand (4/3 palms), shaftment (2 palms), span (3 palms), cubit (6 palms) and ell (15 palms).

Unit Definition (pouce)
The pouce is a French "inch" unit, equal to 1/12 pied. Based on the pied de roi, the pouce equals about 1.066 inches or 2.707 centimeters. The word pouce means "thumb" in French.