Convert from button measure to arpent [Canada]

Unit Definition (button measure)
The button measure is a unit of distance equal to 1/40 inch (0.635 millimeter), used to measure the thickness of buttons.

Unit Definition (arpent [Canada])
The Arpent is a traditional unit of distance in French-speaking nations. It was used as a land measurement, which is the reason for 'Arpentage' becoming the French word for surveying.