Dear John,
You wrote:
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.
Should this Troy ounce be referred to as the metric Troy ounce?
It looks similar to:
* the metric inch – exactly 25.4 millimetres.
* the metric foot – exactly 304.8 millimetres
* the metric yard – exactly 914.4 millimetres
etc.
Cheers,
Pat Naughtin
Author of the forthcoming book, Metrication Leaders Guide.
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
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On 2009/08/06, at 4:12 AM, John M. Steele wrote:
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
