Just surfing the net and found this Burmese system of units
10 hair's breadth = 1 sesamum seed
60 sesamum seeds = 1 (other type of grain)
4 of them = 1 finger's width. http://en.wikipedia.org/wiki/Hair's_breadth
This measurement is not a precise one. Human hair varies in diameter, ranging anywhere from 30 μm to 100 μm. One nominal value often chosen is 75 μm, but this – like other measures based upon such highly variant natural objects, including the barleycorn – is subject to a fair degree of imprecision.
Such measures can be found in many cultures. The English "hair's breadth" has a direct analogue in the formal Burmese system of Long Measure. A "tshan khyee", the smallest unit in the system, is literally a "hair's breadth". 10 "tshan khyee" form a "hnan" (a Sesamum seed), 60 (6 hnan) form a mooyau (a species of grain), and 240 (4 mooyau) form an "atheet" (literally, a "finger's breadth").
Y'know, sometimes I think some wiki-threads are a pisstake.
What would Burmese farmers do with a unit of measure only readable with a strong microscope? 10x60x4 = 1/2400 th of a finger width ...
Yeah right, as they say !! (that phrase when two positives make a negative).
Or maybe they line up all the little seeds and/or hairs) and put em in a small vice? (240 sesame seeds to the finger width - whoever found that out?) Ever tried to pick up three (or more) peanuts with chopsticks?
Also if the lower bound estimate of a hair's breadth is 30 microns, (0.03 mm) then 2400 of them = 72mm , meaning that either Burmese farmers have very broad fingers, or very thin hair ( 2 cents).