Was the metre invented in EnglandWikipedia reported that "He [James Watt] was a
member of the Batavian Society, and one of only eight Foreign Associates of the
French Academy of Sciences." Why would the French have honoured him thus?
Could it have been his work on an active "metric" committee? I don't know the
answer, but it is certainly a proposal that cannot be dismissed out of hand.
----- Original Message -----
From: Stan Jakuba
To: U.S. Metric Association
Cc: Mark Jason Dominus
Sent: Monday, February 05, 2007 4:32 PM
Subject: [USMA:37925] Re: Was the metre invented in England
One of my students claimed that among the proposed "metre" lengths the French
considered, it was James Watt's argumentation for the basic length to be about
a yard long that prevailed. In other words, his arguments were to make the
French to select the 10,000,000 of the Earth's quadrant, rather than some other
division.
I have never been able to confirm this, nor did I see a document confirming
that James Watt was active (corresponding) with the "metric" committee.
Stan Jakuba
----- Original Message -----
From: Pat Naughtin
To: U.S. Metric Association
Cc: Mark Jason Dominus
Sent: 07 Feb 04, Sunday 19:27
Subject: [USMA:37924] Was the metre invented in England
Dear All,
Was the metre, as the universal standard of measurement, invented in
England?
Recently, I discovered a web blog at
http://blog.plover.com/physics/meter.html that suggests that the metre was
invented in England 110 years before the French development of the metric
system.
It seems that John Wilkins was comfortable with a truly universal
measurement standard and on the idea of basing the standard on the
circumference of the earth. However, he ultimately plumped to let the standard
length be the length of a pendulum with a known period.
By the way, in about 1658, John Wilkins was the founding chairman, and
later secretary, of the Royal Society.
The details from Mark Dominus' blog are below.
Cheers,
Pat Naughtin
PO Box 305 Belmont 3216
Geelong, Australia
61 3 5241 2008
Pat Naughtin is manager of http://www.metricationmatters.com an internet
website that primarily focuses on the many issues, methods and processes that
individuals, groups, companies, and nations use when upgrading to the metric
system. You can contact Pat Naughtin at [EMAIL PROTECTED]
Fri, 03 Mar 2006
John Wilkins invents the meter
An Essay Towards a Real Character and a Philosophical Language
I'm continuing to read An Essay Towards a Real Character and a
Philosophical Language, the Right Reverend John Wilkins' 1668 book that
attempted to lay out a rational universal language.
In skimming over it, I noticed that Wilkins' language contained words for
units of measure: "line", "inch", "foot", "standard", "pearch", "furlong",
"mile", "league", and "degree". I thought oh, this was another example of a
foolish Englishman mistaking his own provincial notions for universals.
Wilkins' language has words for Judaism, Christianity, Islam; everything else
is under the category of paganism and false gods, and I thought that the
introduction of words for inches and feet was another case like that one. But
when I read the details, I realized that Wilkins had been smarter than that.
Wilkins recognizes that what is needed is a truly universal measurement
standard. He discusses a number of ways of doing this and rejects them. One of
these is the idea of basing the standard on the circumference of the earth, but
he thinks this is too difficult and inconvenient to be practical.
But he settles on a method that he says was suggested by Christopher Wren,
which is to base the length standard on the time standard (as is done today)
and let the standard length be the length of a pendulum with a known period.
Pendulums are extremely reliable time standards, and their period depends only
their length and on the local effect of gravity. Gravity varies only a very
little bit over the surface of the earth. So it was a reasonable thing to try.
Wilkins directed that a pendulum be set up with the heaviest, densest
possible spherical bob at the end of lightest, most flexible possible cord, and
the the length of the cord be adjusted until the period of the pendulum was as
close to one second as possible. So far so good. But here is where I am
stumped. Wilkins did not simply take the standard length as the length from the
fulcrum to the center of the bob. Instead:
...which being done, there are given these two Lengths, viz. of the String,
and of the Radius of the Ball, to which a third Proportional must be found out;
which must be as the length of the String from the point of Suspension to the
Centre of the Ball is to the Radius of the Ball, so must the said Radius be to
this third which being so found, let two fifths of this third Proportional be
set off from the Centre downwards, and that will give the Measure desired.
Wilkins is saying, effectively: let d be the distance from the point of
suspension to the center of the bob, and r be the radius of the bob, and let x
by such that d/r = r/x. Then d+(0.4)x is the standard unit of measurement.
Huh? Why 0.4? Why does r come into it? Why not just use d? Huh?
These guys weren't stupid, and there must be something going on here that I
don't understand. Can any of the physics experts out there help me figure out
what is going on here?
Anyway, the main point of this note is to point out an extraordinary
coincidence. Wilkins says that if you follow his instructions above, the
standard unit of measurement "will prove to be . . . 39 Inches and a quarter".
In other words, almost exactly one meter.
I bet someone out there is thinking that this explains the oddity of the
0.4 and the other stuff I don't understand: Wilkins was adjusting his
definition to make his standard unit come out to exactly one meter, just as we
do today. (The modern meter is defined as the distance traveled by light in
1/299,792,458 of a second. Why 299,792,458? Because that's how long it happens
to take light to travel one meter.) But no, that isn't it. Remember, Wilkins is
writing this in 1668. The meter wasn't invented for another 110 years.
Having defined the meter, which he called the "Standard", Wilkins then went
on to define smaller and larger units, each differing from the standard by a
factor that was a power of 10. So when Wilkins puts words for "inch" and "foot"
into his universal language, he isn't putting in words for the common inch and
foot, but rather the units that are respectively 1/100 and 1/10 the size of the
Standard. His "inch" is actually a centimeter, and his "mile" is a kilometer,
to within a fraction of a percent.
Wilkins also defined units of volume and weight measure. A cubic Standard
was called a "bushel", and he had a "quart" (1/100 bushel, approximately 10
liters) and a "pint" (approximately one liter). For weight he defined the
"hundred" as the weight of a bushel of distilled rainwater; this almost
precisely the same as the original definition of the gram. A "pound" is then
1/100 hundred, or about ten kilograms. I don't understand why Wilkins' names
are all off by a factor of ten; you'd think he would have wanted to make the
quart be a millibushel, which would have been very close to a common quart, and
the pound be the weight of a cubic foot of water (about a kilogram) instead of
ten cubic feet of water (ten kilograms). But I've read this section over
several times, and I'm pretty sure I didn't misunderstand.
Wilkins also based a decimal currency on his units of volume: a "talent" of
gold or silver was a cubic standard. Talents were then divided by tens into
hundreds, pounds, angels, shillings, pennies, and farthings. A silver penny was
therefore 10-5 cubic Standard of silver. Once again, his scale seems off. A
cubic Standard of silver weighs about 10.4 metric tonnes. Wilkins' silver penny
is about is nearly ten cubic centimeters of metal, weighing 104 grams (about
3.5 troy ounces), and his farthing is 10.4 grams. A gold penny is about 191
grams, or more than six ounces of gold. For all its flaws, however, this is the
earliest proposal I am aware of for a fully decimal system of weights and
measures, predating the metric system, as I said, by about 110 years.
