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

RAILWAYS.

Cash. Account.
Orleans
Northern lOOO .. 1000
New, ditto
Lyons and Mediterranean 1025 .. 1027 50
Geneva..
Southern 740 .. 737 50
Western
Eastern .. ..
Sardinian
—•—• s • "-- --
Austrian
Lorchard
North of Spain
Saragossa.....~, .
Ditto to Barcelona

The Metric System of Weights and Measures

TO THE EDITOR. OF THE SUN.

SlR,—The article against the Metric System in the
Times 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 Tones, but refused admittance.
A. much longer essay in the same strain has just appealed
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 legalis-
ing the Metric System in England in the manner now pro-
posed.
But Mr. Cobden will pardon me if I step aside from the
pursuit of my more direct object to quote his words in the

,triinevited the
Accort-
House of Commons on the occasion of the recent
sdyebztaetnie,
and to subjoin the version of them given by your essayist.
written." It
Go-
wallslor.doCpotbedd,enthesaFilt—en‘o,hßGefoovreerhthmeenFtr,einochl7lN9lor,
English Government to send learned Fellows of our Royal
Society to France to devise a system of weights and mea-
" Ill-
ishugrestoforthteherewproer:odo.
toltVioen dwechliinehedytoouinthearvfeerea.d":pted,
informed persons make the Royal Society responsiblelftorwnaost
attending." Mr. Cobden and his colleagues in the Metric
System agitation throw the blame upon the British Govern-
ment and the nation, At the same time, as :
this writer
tthsuthche Was
sglish
says,Go-
vernment, derdlir
ems
es"endT:t letter:
George (of
111.,n invitation) a
thet io nh)e
awdaosf
and it wee so addressed because Taltlheroannldy
cor-
rect been informed by Sir John Riggs Miller, a member of the
House of Commons, who at that time was the most promi-
nentreet
methodagitator
of
fn
otohmeraquUneisetaiOtinzgthwai
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-
angry and futile
Cobden, Ewart, and their friends"
one theof t them, pursuit
lhoafve reason to acknow-
a
oghreatrgthesatagyootuorstes„%aiyeisstsresh.ould bring these
at a time when their friends are united without any narrow
object,distinctions
when,of pa r party, ,groat and good
ledge with the highest respect and gratitude, the kind re-
ception given to us at one time by Me. Disraeli as Chancel-
lor of the Exchequer, and on subsequent occasions by Mr.
Milner Gibson, as President of the Board of Trade.
da
favour
of the introductionh this ne—"
The second portion of the article, Which appeared yester-
day, commences The great argument
in
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
witsente
of e
of the arc of the meridian being, as the Metric 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 ,P is seldom, perhaps
never, used. Ira 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
occupies 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 metro is sufficiently accurate for all practical pur-
poses, ar d as truly an ascertained aliquot part of the
meridional quadrant as any other measure that has been,
or can, at least under present circumstances, be proposed.
Tho 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 there 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
painted 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

I send here, with the Debate of the House of Com-
mons, including Cobden's Speech, corrected by himself,