Convert from gnat's eye to arpent [France]

Unit Definition (gnat's eye)
The gnat's eye is an idiomatic "unit" of distance; it's common to hear that something is "as small as a gnat's eye". In fact, the eyes of typical gnats tend to have diameters similar in size to a hair's breadth: roughly 100-150 micrometers (0.10-0.15 millimeters).

Unit Definition (arpent [France])
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' becomming the French word for surveying. It has an official definition of 191.835 English feet (58.471308 meters).