Ay up Bill (Potts) I ant got foggiest what Tom is lakin abart at
Whats ROTLF when its at ome? ~~~~~~~~~~~~~~~~~~~~~~~~ (right out of left field would be different anyhow) ~~~~~~~~~~~~~~~~~~~~~~~~ Tom: Both Indian and Egyptian weight systems were basically decimal above the unit and binary below the unit prior to 2000 BC - because that was appropriate to their technology (ie 2-pan scales) (Hindu Unit = 128 ratti seeds ca 13.71 grams = the 'suvarna'. Egyptian unit - 256 wheat grains - two or three 'absolute' standards between about 12.2g to 13.8 grams = the 'beqa'). If you peel back a few layers of deceipt then imperial is at bottom much the same - 16 oz to the pound, 100 pounds to the cwt. Why the Babylonians went for a sexagesimal system (with a sub base 10) is unknown - it defies the technology of the times - but it likely has a lot to do with the nice set of fractions base 60 maths throws up. And the fact that bankers prefer 1/12's or 1/60's 'cause its easier to mentally divvy up, calculate interest etc. When the Athenians adopted their drachm from the Persian/Babylonian half shekel (date unknown but late pre-history) they made it 100 rather than 120 to a pound (ie mina). Best to skip the Romans - they maybe got their numerical system from the neandertals and skipped cro-magnon developements (joke) The Chinese Tang dynasty reset the calendar to year 1 back in 622 AD (as best I recall) - like the French revolutionaries. And they made 10 cash to the ounce, 1000 copper ounces to the gold ounce as best I understand it. So they are the first 'fully' decimal currency system I know about. Pat raises some stuff re decimal fractions which seems to me a slightly different matter but is very interesting. I do not know the way they got popularised. I guess they are vital to compiling log tables, and sensible on slide rules, but I do not know how things developed. Certainly they were the big vogue about 1720 when Berkeley was a young guy. Our decimal notation system for the numbers above 0 'the sindhind' developed in India prior to 450 AD (as is well known) - but when the Arab Alberuni investigated Hindu estimates of Pi around about 1000 AD he found their most sophisticated guess to be 3 + 177/1250. (actually thats Alberuni - the Hindu guy wrote 1,256,640,000/400,000,000). It looks to me like these guys were not too dumb with numbers? But they not using decimal fractions - and its not obvious to me that in 1000 AD there would be any advantage to a mathematician in using them - quite the reverse. Maybe I'm missing something here? Best rob (a tyke by birth) PS All: the pope is a catholic
