On Tue, 16 Sep 2003 00:11:55 +1200, Russell McMahon wrote: >...< >It's not the base that matters but the fact that ALL > measurements are expressed in terms of the same base. You could have a= > measurement system using, say, base 60 ("better" because it has more f= actors > :-) (2,3,4,5,6,10,12,20,30)) as the Babylonians did and, as long as a= ll > sub-units scaled down in base 60 as well, the system would be fine. It= 's > when you start changing the base at different arbitrary points along t= he way > so that you cannot perform consistent computations with the units, tha= t you > have problems. > > Inconsistent: > (Farthing, halfpenny), penny, shilling, pound, guinea. > Ounce, pound, hundredweight, ton. > > Consistent: > (Angstrom), nanometre, micrometre, millimetre, (centimetre), > (decimetre), metre, kilometre, ... > Srob, bleck, glurb, tchum (I made these up) > > All base 10: > 1 bleck =3D 60 Srob, > 1 glurb =3D 3600 Srob =3D 60 bleck > 1 tchum =3D 216,000... > > Units in brackets do not really belong in each series per se. Now this is an interesting point - what you have above is two things com= bined, a unit (metre) and scale (milli, deci, etc) and we use them as if they are a single entity. The = same happens with inches, but new names have been made up for brevity. Instead of saying a "dozeninch" we= say "foot". So as I see it, the two things making metric measurement easier to handle are its use of base-10= for all scaling, and its use of standard scaling factor names across the board. So we know that if a mi= llimetre is 1 metre/1000, we know without being told that a millilitre is 1 litre/1000. The Imperial syst= em is harder because it uses different scaling factors and different names for the scaled measurements, or at l= east it usually does... You would have liked the scheme used in a firm I used to work for, which= made stationery. Books were counted like this: 1 Book =3D 1 Twelfth 12 Twelfths =3D 1 Dozen 12 Dozen =3D 1 Gross 12 Gross =3D 1 Great Gross When they did physical stock checks they would write on the sheets somet= hing like: 0 / 4 / 2 / 6 and someone sat at a computer keyboard would convert it using mental arithmetic or a= calculator, into numbers that they could enter into the system. The warehouse system that I designed dealt= with *all sorts* of units of measure, but I drew the line at having base-12 multiple units like this, especial= ly as they never had packs of less than three books anyway, so they entered it in dozens with up to 2 decim= al places. (By the way the total of the above is 606 books, or 50.5 dozen! :-) > Now if a hundredweight had been 125 pounds it may have made some sense= :-) > Or somewhere about 128 pounds so that it was the force from something = that > massed 4 slugs. > But 112 pounds is useful mainly to terrorise students. Well it came from 8 Stone to the hundredweight, but quite why a Stone is= 14lbs I really can't fathom! :-) A half-hundredweight is very close to 25kg though, so it's handy for sacks= of potatoes... > A guinea is an affectation :-) Indeed, it was used for auctions where the seller got the =A3 and the au= ctioneer got the shilling, so it was basically an easy way to express a 5% premium. It was probably decimali= sed to =A31.10 - almost everything else went up as a result of going to =A31 =3D 100 New Pence :( Cheers, Howard Winter St.Albans, England Who was it who said "Gross indecency =3D 144 times worse than normal ind= ecency" ? :-) -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.