Very interesting. I'm sure there's a perfectly logical explanation for the units. I supects it's something to do with angles rather than linear measurement. 60 minutes = 1 degree etc. The earliest method of measuring time was with a sundial.
The Metric system (based on units of 10) wasn't in general use until quite recently. (I always blamed that little Frenchman for it.) Prior to that all units of measurement were based on natural things, like one inch being the length of the first joint of a man's thumb. A tradesman can measure something reasonably accurately using the Imperial system without any tools, gauges or other artificial aids. I can remember drapers measuring cloth by the old trick of holding it up to their nose with the other arm outstretched, This would be one yard (3 feet) & quite fascinating to watch an experienced person do it. This wouldn't be allowed now but with the little bit extra "for luck" they always gave you it was perfectly acceptable to customers & surprisingly accurate. I don't remember anyone complaining about being cheated.
I don't know the origin of the dozen (units of 12) but it goes way back in history & might have something to do with the number of hours in a day. Even in the days of the GPS, navigation is still based on minutes & seconds. We were discussing only the other day that 1 nautical mile = 1 minute of latitude.
This is why I always had difficulty with visualising metric measurements. They don't seem to be based on anything natural, in fact I consider them most unnatural.
