The Sun.
London, England, 1863-09-29 00:00:00

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The Metric System of Weights and Measures

TO THE EDITOR. OP THE SUN.

SlR,—The article against the Metric System in the
limes of July 9, signed 8., has been already answered by
Mr. Charles Hutton Dowling, C.E., in the London Review
of August 1, and by Mr. Frank Fellows, of Wolverhampton,
in the Daily News of Sept. 7, his answer having been first
sent to the Times, but refused admittance.
A. much longer essay in the same strain has ju3t appeared
in the Times of Tuesday, Sept. 15, and of yesterday, and to
this I now wish to reply, In the first part (Times, Tuesday,
Sept. 15), there is only one passage which seems to require
notice from me. All the observations in regard to the
thermometer, the dimensions of the great pyramid, and the
measurement of degrees, though tolerably correct, have
nothing to do with the question of the propriety of legaiis.
pinegsed.
the Metric System in England in the manner now pro-
But Mr. Cobden will pardon me if I step aside front the
pursuit of my more direct object to quote his words in the
House of Commons on the occasion of the recent debate,
anti
Mr. to subjoin
Cobden the
sail—"version
Before of them
the
Frenchgiven b youry essayist.
Metric
System
was adopted, the French Government, in 1790, invited the
English Government to send learned Fellows of our Royal
Society to France to devise a system of weights and
mea-
sures for the world. We declined to interfere,".
Accord-
ingthis writer
to the representation which you have adopted, " Ill-
informed persons make the Royal Society responsible for not
attending." Mr. Cobden and his colleagues in the Metric
System agitation throw the blame upon the British Govern-
meatsays,
"Thea nd th
eletnt It was
addressed to George 111., as the head of the English aertio(ne,f
inAvtitathtieens)amweastivrmreiltasea.,.
Go-
vernment, and it was so addressed because Talleyrand had
been informed by Sir John Riggs Miller, a
member of the
House of Commons, who at that time was the most promi-
nent agitator on the question, that such was the only cor-
rect method of communicating with the English Govern-
ment, It may be true, as your correspondent suggests, that
George 111. suppressed the letter, but it is admitted by him
as an undeniable fact that the French Government, through
Louis XVI. as its head, did communicate with the English
Government by the only regular and legitimate ' channel.
With respect to the alleged accusations against the Royal
Society, I doubt whether such accusations have ever been
made, and lam persuaded they were not deserved. I re-
gret that your essayist should bring these angry and futile
charges against '° slessrs.Cobden, Ewart, and their friends"
at a time when their friends are united without any narrow
distinctions of party, in the pursuit of a great and good
object, and when, as one of them, I have reason to acknow-
ledge with the highest respect and gratitude, the kind re-
ception given to us at one time by Mr. Disraeli as Chancel-
lor of the Exchequer, and on subsequent occasions by Mr.
Milner Gibson, as President of the Board of Trade.
The second portion of the article, which appeared yester-
day, commences with this sentence---" The great argument
in favour of the introduction of the Metric System here
has been its extreme mathematical accuracy, and the pre-
sumed ease with which the Standard could be recovered
and verified in case of the original being destroyed." It is
added, "We have been told, that instead of the quadrant
of the arc of the meridian being, as the Metrie System sup-
poses it to be, 10,000,000 metres, it is 856 metres more ;"
and it is inferred, that
" this fundamental error necessarily
vitiates the whole system of weights and measures, and that
the kilogrammes should be augmented by 257 milli-
grammes.,, In all this it appears to me that your author
is in error. This "great argument" is seldom, perhaps
never, used. In support of this remark I may be per-
mitted to quote pretty largely from a pamphlet published in
1858 by the International Decimal Association as the re-
sult of their inquiries in regard to " the Best Unit of
Length," in which the examination of this very question
occapies 15 pages. " The fact appears to be, that in the
process of measuring the earth, no less than in experiments
with the pendulum, absolute accuracy is unattainable ; but
that the metre is sufficiently accurate for all practical pur-
poses, at, d as truly an ascertained aliquot part of the
meridional quadrant as any y other measure that has been,
or can, at least under present circumstances, be proposed.
The authors of the Metric System never hoped, or pre-
tended to arrive at, perfect exactness in the measure of the
earth. They knew that no measurement whatsoever can
be mathematically accurate, such accuracy being expressed
only by imaginary, not real lines. Their endeavour was,
by the use of the best instruments, by repeating their ob-
servations, by taking
every precaution for the avoidance of
error, and by making all the corrections, which were proved
to be important, to come as near as possible to a true result.
No one has denied that their exertions, marked as they
were by energy, perseverance, and self-sacrifice, no less
than by ability of the highest order, have entitled them to
the admiration and gratitude of all enlightened men. Since
the completion of their labour, the measurement of meri-
dional arcs has been undertaken by other parties, and, of
necessity, with a slight difference in the results. The
improvements suggested by experience and by the advance
of science have been carefully introduced, In former
instances, prior to Mechain and Delambre's measurement,
an angle was thought to be sufficiently defined by a church
tower, or a pile of stones ; more recently a mirror, or a
pain • ted circle of wood, has been fixed on the summit of the
previous object, and, if large enough to be distinguished at
the assigned distance, it has admitted of greater nicety in
the observations. On such grounds philosophers are natu-
rally disposed to prefer the more modern conclusions, and
the consequence is, that if the metre were now to be deter-
mined, it would probably be made larger than the
established metre, by a quantity, which though not obvious

send here, With the Debate of the House of Cora-
ine
ucthag
cobdowe
Speech,
corrected by himself,