I agree on troy ounces, not on troy pounds. I offer this: http://www.sizes.com/units/ounce_troy.htm In the English-speaking world, at least as early as the 12th century – present, a unit of mass now used only for precious metals, = 31.103 476 8 grams = 1/12 troy pound = 480 troy grains, each traditionally the mass of a grain of barley. The troy ounce is identical to the apothecaries' ounce, formerly used for drugs. It is the last unit in troy weight remaining in regular use, and then only in the United States. In the United Kingdom, when the troy pound was abolished in 1878, the troy ounce was retained for weighing precious stones and metals. The Weights and Measures Act of 1963 restricted use of the troy ounce to the weighing of precious metals. The Weights and Measures Act of 1985 redefined the troy ounce as 12⁄175 of 0.45359237 kilogram. I would also note the Wall Street Journal quotes commodities futures, and the price is per troy ounce, while contracts are 100 troy ounces (gold), 50 troy ounces (platinum) and 5000 troy ounces (silver). As none of these are divisible by 12, I believe the troy pound is no longer used in the US in a practical sense. However, since it is mentioned in NIST Handbook 44, Appendix C, it is apparently not "abolished" as it is in the UK.
--- On Wed, 8/5/09, James R. Frysinger <[email protected]> wrote: From: James R. Frysinger <[email protected]> Subject: [USMA:45514] Re: Neat chart of English mass units To: "U.S. Metric Association" <[email protected]> Date: Wednesday, August 5, 2009, 1:35 PM Troy pounds and Troy ounces have long been and I believe still are used in the U.S. trading in precious metals. I believe that (Troy) pennyweights fall into that category, too. Jim John M. Steele wrote: > Maybe, superb chart of units of mess? :) > If I look at how they handled the various pounds, the av. lb and stone lead >to different quarters, hundredweights and tons, which should be set up as >separate ellipses, particularly since the long and short ton and its >subdivisions are a modern "two peoples divided by a common language" issue. > As far as I know the troy pound (and all the others except av. pound) is not >legal for trade in the US or UK, and has no real relevance. However, the troy >ounce continues for precious metals. > > --- On *Wed, 8/5/09, James R. Frysinger /<[email protected]>/* wrote: > > > From: James R. Frysinger <[email protected]> > Subject: [USMA:45511] Neat chart of English mass units > To: "U.S. Metric Association" <[email protected]> > Date: Wednesday, August 5, 2009, 11:45 AM > > > Wow! This is a superb "graph" (I call it a chart) of the units of > mass (commonly called "weight") used in England and the numerical > relationships among them. So far as I can tell it's accurate; it > jibes with the numbers and history that I know. For one, you can see > where that figure of 5760 grains per Troy pound came from! > > You will see on here 5 "pounds" listed and they all differ in size. > A similar situation in France is what led them to chuck out the > whole mess and to devise a "simple decimal system" that we now call > the metric system. > > http://en.wikipedia.org/wiki/File:English_mass_units_graph.svg > -- James R. Frysinger > 632 Stony Point Mountain Road > Doyle, TN 38559-3030 > > (C) 931.212.0267 > (H) 931.657.3107 > (F) 931.657.3108 > -- James R. Frysinger 632 Stony Point Mountain Road Doyle, TN 38559-3030 (C) 931.212.0267 (H) 931.657.3107 (F) 931.657.3108
