Elementary arithmetic, with brief notices of its history... by Robert Potts.

WEIGHTS AND MEASURES.

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declares that " for the promotion and extension of the internal as well
as of foreign trade, and for the advancement of science, it is expedient
to legalise the metric system of weights and measures." The convenience and utility of any system of weights and measures constitute
the chief reason for retaining them, and any proposal to substitute
a new for an old system which has been for ages deeply imbedded in
the laws, the customs, and the habits of a people, appears to be at
least a matter of doubtful expediency. It may be observed that the
retail trading transactions of the mass of the population, and the
exactness of scientific inquiry, do not require the same weights and
measures. The weights and measures that would be proper for retail
trade would be unfit for the exactness of scientific investigation. The
past history of the progress of science owes little, if anything, to the
French metric system for its advancement; and it is not obvious how
in future it could be employed for this purpose, so as to secure,
by its employment, any advantages which have not been already
secured by the system long employed in England. The decimal system
has been, and still is, largely employed both in measures and calculations where its use has been found to be convenient, and will continue
to be so employed.
The decimal division of the British coinage, though very strongly
advocated,l has not been authorised by the Act which legally permits
the use of the decimal system of weights and measures. It is possible
that in some trades and manufactures the use of it may suggest
some improvements, without superseding the established system,
which is understood and suited to the wants of the people.
The opinion of the late Sir J. W. F. Herschel, in 1864, on the
standards of measure, is worthy of consideration:-" Whatever be
the historical origin of our standards of weight, capacity, and length,
as a matter of fact our British system refers itself with quite as much
arithmetical simplicity, through the medium of the inch, to the earth's
polar axis as the French does through that of the metre to the elliptic
of the measure proposed for adoption. Mr. Ewart had forgotten that the construc.
tion of a perfect and just standard is the first step in legislation on such subjects.
1 The merchants and bankers of the City of London in one of the most influentially-signed petitions which ever emanated from the city, presented in 1855,
use language on this subject which is hardly that of petitioners. They say, that
"the pound constitutes an English national fixed idea of value and position, and is
associated with every existing contract, and every comparison of past revenue,
expenditure, and price, and must be retained." They say, also, that every other
method, except that from the pound downward, is altogether impracticable.
We feel perfectly easy in our reliance on the common sense of the country, that it
will not hear of the expulsion of the pound sterling from accounts, while the
sovereign is to be retained as means of payment, after division by 24; that it will
not hear of the mixed circulation of shillings and tenpences; that it will stick to
its old and successful plan of reforming that which is, instead of Substituting that
which has never been, especially in matters connected with our oldest habits of
estimation, usages of action, and associations of thought.... If, however,
the shillings and sixpences could be replaced by an equivalent amount in tenpenny
and fivepenny bits, in the course of a single night, and by the wand of a magician,
the country would find itself in a poor state in the morning. Every idea of value
would be upset; all notions of cheapness and dearness would require translation.
A man who had made up his mind over night that he would go as far as ~1 17s. for
a purchase, must take pen and paper, if not more ready than usual, to find out how
many francs he may venture upon. And this would last for years with many, for
months with all. And for what? To avoid an alteration in the copper coin, which
would amount to a little short of one farthing in sixpence.-Professor De Morgan.