Avoirdupois, Troy, Apothecary[複數Apothecaries]
grain 在這三種系統是等重的
i.e. 1 grain = 1 troy grain =1 avoirdupois grain = 1 apothecaries grain
//=== Avoirdupois :
1 pound = 1 lb = 453.59237 g == 1 av pound == 1 pound av
1 ounce = 1 oz = 1/16 pound = 28.349523125 g == 1 oz av == 1 av oz
1 dram = 1 dr = 1/16 oz = 1/256 pound
1 grain = 1/7000 pound = 0.06479891 g
玉米, 小麥, 大麥的重量單位
1 bushel (corn) = 56 lb = 25.4012 kg
1 bushel (wheat) = 60 lb = 27.2155 kg
1 bushel (barley) = 48 lb = 21.7724 kg
//=== Troy, 目前主要用於金屬及寶石的重量表示
Troy 就是木馬屠城記的特洛伊城, 比較常見的是他的形容詞trojan
(因為電腦病毒 ... )
troy pound(lb t) == pound troy == libra
troy ounce(oz t) == ounce troy
1 troy pound = 12 troy ounces = 5760 grains = 144/175 pound av
1 troy ounce = 1/12 troy pound= 12/175 pound av= 31.1034768 g
1 pennyweight= 1 dwt = 24 grains = 1/20 troy ounce
1 troy pound = 12 troy ounces = 240 pennyweights = 5760 grains
新聞中常聽到的黃金價格每盎司1700USD 指的就是 1700USD/31.1034768g
也就是每公克大約 54.656USD -> 每公克大約 54.656 *30 NTD = 1639.7 NTD
令
1 troy ounce = x g,
1 USD= y NTD
當 x=y 時
黃金每盎司的價格 u USD
黃金每公克的價格 n NTD
u=n
[金的元素符號是Au，原子序是79, Au -> Aurum -> Aurora]
//=== Apothecaries, not used now
" The avoirdupois pound contains 7000 troy grains; so that 175
pounds troy equal 144 pounds avoirdupois, or 1 pound troy
= 0.82286 of a pound avoirdupois, and 1 ounce troy =
117/175 or 1.09714 ounce avoirdupois. Troy weight when
divided, the pound into 12 ounces, the ounce into 8 drams,
the dram into 3 scruples, and the scruple into 20 grains,
is called apothecaries' weight, ...
"
[ref]
http://cdict.net/?q=troy
http://en.wikipedia.org/wiki/Grain_(unit)
http://en.wikipedia.org/wiki/Avoirdupois
http://en.wikipedia.org/wiki/Troy_weight
http://en.wikipedia.org/wiki/Gold
