Re: feather or lead




Weights

Weights (Avoirdupois) Weights (Troy and
Apothecaries) Jewels Rough conversion
between Imperial and Metric


Weights (Avoirdupois)
Units of weights 16 dram = 1 oz
16 oz = 1 lb
14 lb = 1 st
2 st = 1 qtr
4 qtr = 1 cwt
20 cwt = 1 ton
Abbreviations oz - ounce
lb - pound
st - stone
qtr - quarter
cwt - hundredweight

Gram Kilo Dram Ounce (oz) Pound (lb) Stone
Quarter Hundredweight (cwt) Ton
= Gram Kilo Dram Ounce (oz) Pound (lb) Stone Quarter
Hundredweight (cwt) Ton

= Gram Kilo Dram Ounce (oz) Pound (lb) Stone Quarter
Hundredweight (cwt) Ton

Enter number and select unit.
Select other units for conversion.


The abbreviation for hundredweight is "cwt" because "C" is
the Roman symbol for 100. It is called a hundredweight
because it is 112 lb (well, it's close!). It can also be
called the long hundredweight to distinguish it from what
the Americans call the short hundredweight, which is 100
lbs. So the long ton or UK ton is 2240 lbs, and the short
ton is 2000 lbs. The metric tonne is 1000 kg (about 2205
lbs). The word "ton" is derived from the same source as that
of a tunne of wine, a cask which held about 250 gallons.
Tons were in use in the late 15C.

A dram is short for a drachm, but since the avoirdupois
drachm is different from the apothecaries drachm, it could
be that the name "dram" was used to help distinguish it.
These different types of weight measurement are a confusion
anyway. The kilogram is at least well defined without having
to say which system you're using! Scots use 'dram' to mean a
small glass, probably of whisky! I don't think this is
connected with the weight measurement dram.

A pound is always written as "lb" to prevent confusion with
pound money "£". It is very old, traced back to the Roman
"libra" (which explains its abreviation!). It was defined in
England since Ethelred the Unready (968-1016). In fact, a
pound (money) was originally a pound (weight) of silver, and
the symbol for pound (money) £ is a stylised L.

The abbreviation for ounce is "oz". This comes from 15th
century Italian, also "oz" which is an abbreviation of
"onza". "Oncia" seems to be the modern Italian for ounce
(although they use metric measures now, of course) and I
suppose that "onza" is a variant of this. The word "ounce"
comes from the Latin "uncia" or twelfth part. The ounce is a
sixteenth part of a pound avoirdupois, but it used to be a
twelfth part of a pound troy. Troy weights are now only used
for precious stones and metals (and not even for that,
much), but they used to be the normal measure of weight. See
a Tudor set of measures.

Winnie the Pooh wrote a poem about Tigger:
"But whatever his weight in pounds, shillings and
ounces,
He always seem bigger because of his bounces."
Piglet didn't think that the shillings ought to be there,
but Pooh explained "They wanted to come in after the pounds,
so I let them. It's the best way to write poetry, letting
things come." (The old sterling money (pre-decimal) was
£.s.d or "Pounds, shillings and pence".)

Rob (aged 11) has pointed out that, strictly speaking, lb
and oz measure mass, not weight. However, the old school
books had tables on the back of them headed 'Weights and
Measures', so since this is really a history website rather
than a scientific one, I'm afraid that I shall continue to
use the word 'weight'! Rex adds to the debate by saying
"Pounds measure force, not mass (a weight is a force). The
unit of mass in the Imperial system is a ridiculous unit
called a "slug," which weighs 32 pounds avoirdupois under
standard conditions. I've had further correspondence about
this, which has led me to do a little research (well, I've
googled a page or two!) There does seem to be a confusion
here. When I did Physics A level in 1970, we were taught
that pound (lb) was a unit of mass, wheareas pound weight
(lb wt) was a unit of weight. However,
scienceworld.wolfram.com says that the pound or pound-force
is the unit of weight and the pound-masses is the unit of
mass, although slugs are more used. However here, they admit
that different authors use pound for either mass or weight.
I suspect that this is a difference between American and
British usage. The British obviously decided that if they
were going to buy apples on the Moon, then they wanted a
pound of apples to contain the same number on Earth, so it
should be mass. The Americans said rather that they wanted a
pound of apples to feel the same on the Moon as the Earth,
so it should be force. Personally, I refuse to buy a slug of
apples wherever I am!
A further American comment: "In my experience, the folks who
insist that pounds are always a unit of force tend to be the
physics students (probably to make F=m*a easier on
first-semester students) while the engineering students will
use pounds more as a mass. Ultimately, Congress defined the
pound in terms of grams (not Newtons) in the 1890's, and in
the 1950's the remnants of the foot/pound using world got
together and standardized on the same number of grams, so
"pound" is definitely a unit of mass. Of course, there's
still "pounds of force" used, abbreviated "lbf," but that
has to be differentiated from "regular pounds." When you
think about it, it makes sense that the pound, like the
kilogram, is a unit of mass. The standard has always been a
solid object, and in order to compare what you want to know
the "weight" of in terms of this standard, you'd have to use
a beam balance, which ultimately measures mass. The slug, as
I mentioned before, is simply a convenient unit to use so
that it takes 1 lbf to accelerate it 1 ft/s^2. Before non-SI
metric units fell into disuse, there was a similar unit
called the "hyl," where 1 "kilogram of force" would be
enough to accelerate it 1 m/s^2."

Wool used to be measured in tods. A tod was 28 lbs, or 2
stone. For some reason, the plural of stone is also stone -
like sheep, come to think of it!

Coal on Tyneside was measured in chaldrons of 53 cwt, and
keels of 8 chaldrons or 21 tons 4 cwt. There were 8
Newcastle chaldrons to 15 London chaldrons. A London
chaldron contained about 28.5 cwt or 36 heaped Winchester
bushels. There was plenty of scope for misunderstandings in
the coal trade 200 years ago.

Lead was worked in bings containing 8cwt of clean ore. The
ore was refined into pigs of 1.5 cwt, and these pigs were
sold by the fother containing 14 pigs for a total of 21 cwt.
Silver was recovered from the lead at about 8 ozs per
fother, although in the Alston area about 42 ozs of silver
per fother were recovered.

Americans measure their own weight in pounds rather than
stone. So here is a conversion table.

1 st = 14 lb
2 st = 28 lb
3 st = 42 lb
4 st = 56 lb
5 st = 70 lb
6 st = 84 lb
7 st = 98 lb
8 st = 112 lb
9 st = 126 lb
10 st = 140 lb
11 st = 154 lb
12 st = 168 lb
13 st = 182 lb
14 st = 196 lb
15 st = 210 lb
16 st = 224 lb
17 st = 238 lb
18 st = 252 lb
19 st = 266 lb
20 st = 280 lb


An email from a 60 year old from Dallas, Texas, said: "We
still sell berries by the pint in this country, but potatoes
are sold by the pound. Potatoes used to be sold by the peck.
If my parents were alive they would be 100 and 101. Since I
haven't bought nails in years, I don't know how they are
sold in bulk rates today. When I was a child, my father
would send me to the hardware store by 10 penny nails by the
pound. Today they are sold in plastic bubble packages."
In Britain, we still sometimes buy prawns and shrimps by the
pint, but I've not heard of fruit being sold that way.
Strawberries are often sold by the punnet (a small cardboard
basket), but most berries are sold by weight. Potatoes were
sold by the pound, or stone if you bought enough. Now it's
all kilos, of course.



--------------------------------------------------------------------------------


Weights (Troy and Apothecaries)
Troy Weight 24 grains = 1 pennyweight
20 pennyweight = 1 troy oz
12 troy oz = 1 troy lb
Apothecaries Weight 20 grains = 1 scruple
3 scruples = 1 drachm
8 drachms = 1 apothecaries oz


Troy weight is a system of weights used for precious stones
and metals. The troy pound is no longer in legal use, but
gold is still sold in troy ounce bars. Apothecaries weight
was used for measuring drugs and medicines. Both systems had
the grain, ounce and pound in common (since a troy ounce was
the same as an apothecaries oz).

A pennyweight was called that because it was the weight of a
silver penny.

A scruple is derived from the Latin for a small stone,
because it's a very small weight. We also use scruple to
mean your conscience pricking you like a small sharp stone
in your shoe!

These weights were not learned at school, because they had
very specialised use. But our normal weights tables were
always marked as avoirdupois (which comes from Old French
"to have weight"). The troy system dates from the 10C. The
troy pound was defined as different from the avoirdupois
pound in the reign of Elizabeth I (1558-1603). See this
Tudor set of measures, where the table defines troy weights,
and then separates avoirdupois and troy weights without
giving the conversion factor!

1 troy oz = 480 grains
1 troy lb = 5760 grains
1 oz avoirdupois = 437.5 grains
1 lb avoirdupois = 7000 grains


There is an old joke "Which is heavier, a pound of lead or a
pound of feathers?" Of course, they weigh the same. But if
you said "Which is heavier, a ounce of gold or a ounce of
feathers?", then you could claim that the gold is measured
in troy and the feathers in avoirdupois, and so the gold is
indeed heavier. But a troy pound of gold is lighter than a
pound (avoirdupois) of feathers!
The weight of feathers in a vacuum is different than those
same feathers at STP (buoyant force, Archimedes' Principle).
In fact, if you took a pound (mass) of lead and feathers,
and weighed them on scales (on Earth, which has an
atmosphere), the lead would be heavier. This is because the
feathers displace more air (for non-scientists, something
similar to what makes things float.)
The original joke depends partly on getting weight and
volume muddled up. However, we also know that if you dropped
a feather, and a piece of lead, the feather would take
longer to drop as it would float off to one side then the
other. This is because of air resistance. One of the
experiments when men went to the Moon was to drop a feather
and a piece of lead together. It looked extremely strange to
see them drop at the same speed!



--------------------------------------------------------------------------------


Jewel weights
Troy weight (see above) was used for precious metals and
stones. But individual stones may be described using carats.

200 milligrams = 1 carat
100 points = 1 carat

Carat is derived from "quirrat", Arabic for the seeds of the
coral tree, which were the traditional weights for precious
stones.

There is a different meaning for "carat". 24 carat gold is
pure gold. 18 carat gold is 18 parts of gold to 6 parts of
other metals. 9 carat gold is mostly something else!. The
Americans spell this measure of purity "karat" to
distinguish it from the other sort of carat.



--------------------------------------------------------------------------------


Rough conversion between Imperial and Metric
I find many Imperial to Metric conversions very irritating,
because they are far too precise. So here are some rough
conversions which you can carry in your head.


A smartie weighs about a gram.

A pack of butter weighs 250 grams or a quarter of of
kilo.

A bag of sugar weighs a kilo.

If you're buying fruit and veg, then (very roughly)
1lb is half a kilo.


Here is a mnemonic for remembering weight imperial to metric
conversion:

"Two and a quarter pounds of jam weigh about a kilogram" (or
of course anything else!)
Here is a rough conversion chart:

Accurate to
10gms up to 1lb 8oz
and 20 gms above
1 oz = 30 gm
2 oz = 60 gm
4 oz = 110 gm
8 oz = 230 gm
12 oz = 340 gm
1 lb = 450 gm
1 lb 4 oz = 570 gm
1 lb 8 oz = 680 gm
1 lb 12 oz = 800 gm
2 lb = 900 gm
Accurate to
1/2 oz up to 1 lb
and 1 oz above
100 gm = 3.5 oz
200 gm = 7 oz
300 gm = 10.5 oz
400 gm = 14 oz
500 gm = 1 lb 2 oz
600 gm = 1 lb 5 oz
700 gm = 1 lb 9 oz
800 gm = 1 lb 12 oz
900 gm = 2 lb
1 kilo = 2 lb 3 oz


If you want an accurate conversion:

1 oz = 28.35 gm
4 oz = 113.4 gm
8 oz = 226.8 gm
12 oz = 340.2 gm
1 lb = 453.59237 gm

1 gm = 0.035 oz
100 gm = 3.527 oz
250 gm = 8.82 oz
500 gm = 1 lb 1.6 oz
1 kilo = 2 lb 3.27 oz



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"Robert M. Gary" <N7093v@xxxxxxxxx> wrote in message
news:1140763673.564128.142990@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
|A pound of duck will always out weigh a pound of lead,
especially when
| owned by a witch.
|


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