Having shown in the preceding pages that in the point of view of
scientific accuracy the yard, mètre, and toise standards are on a
common level, and that in the matter of comparisons there is no extreme
accuracy, I will now refer to the proposed change of our standard from
the yard to the mètre.
Theoretically the mètre is the 10,000,000th part of the earth’s quadrant,
and the yard the 36/39·13929th part of a seconds pendulum at London.
Practically, neither the mètre nor yard could be recovered with exactness
from their natural basis. The legal French mètre differs from the
latest reduction enough to give an excess of over three miles to the
circumference of the earth. In fact, the mètre and yard are only the
lengths of bars of metal kept in certain offices, from which copies are
made. Decimally considered, it is as easy to divide one as the other into
tenths, hundredths, etc., and the yard standard is often so divided.
As to nomenclature, the metrical system is overloaded with Greek and
Latin prefixes, which are in no way so easy and convenient in expression
as the short, sharp Anglo-Saxon words yard, foot, inch.
In all sciences Latin and Greek names are given for easier purposes
of classification; but the different peoples invariably keep their
own household names for daily purposes, leaving prefix and affix to
specialists, probably with advantage to both parties.
The units used for different purposes are entirely distinct from the
base of any system, and though always referable to such base, are not
practically so referred. It therefore seems useless to burden the people
with long scientific names in the ordinary transactions of daily life.
For long distances the units in the yard and metrical systems are
respectively the mile and the kilomètre.
The mile has a definite meaning in our minds, being associated, from the
days of youth, with the measured distances in race-courses, speed in
walking, railway and steamer travel, length of surveyed lots--the same
being in use among about 100,000,000 people.
For mechanical structures, the units are respectively the foot and the
mètre. The foot is used instead of the yard, as being the most convenient
in practice, and is fixed in the minds of the people by constant
association with length of foot-rules, size of buildings, doors, windows,
etc., all of which are always before us.
For commercial purposes the units are respectively the yard and the
mètre. The yard is associated with length of yard-sticks, distance
between brass nails on counters, so many finger-lengths by ladies.
Probably three fourths of the business of the world is conducted on the
yard standard.
For machine and shop work the English unit is the inch and fractions,
and countries having the metrical standard have universally adopted the
millimètre.
The inch is well fixed in the minds of all mechanics by constant use, and
the ease with which the fractions are had by halving only renders the
system very convenient.
As more figures must be used to indicate a size by millimètres than by
inches and fractions, it appears that the metrical system cannot shorten
the work of arithmetical computation in shop work, and is therefore of no
advantage to the mechanic or draftsman, but rather the reverse. This is
the opinion of Coleman Sellers, the distinguished Philadelphia engineer
and manufacturer, who, after a trial of the millimètre in his shops for
some years, returned to the use of the inch, and writes in _Engineering
News_: “The loss from the use of a small unit requiring many figures
to express what is needed, takes away from the other advantages of the
system when considered from a labor-saving point of view.”
In France itself the metrical system is not wholly decimal in actual
practice, as we find the following measures in use in addition to the
decimal divisions: double decamètre, demi-decamètre, double mètre,
demi-mètre, and double decimètre.
The metrical system has been adopted in the following countries: France
and colonies, Holland and colonies, Belgium, Spain and colonies,
Portugal, Italy, Germany, Greece, Roumania, British India, Mexico,
New Granada, Ecuador, Peru, Brazil, Uruguay, Argentine Confederacy,
Chili, Venezuela; and partially in Wurtemburg, Bavaria, Baden, Hesse,
Switzerland, Denmark, Austria, and Turkey.
In the past centuries all the work and records of English-speaking
peoples--now numbering about 100,000,000, and increasing and progressing
faster than all other nationalities, as well as being closely connected
by descent and business--have been done and recorded under the yard
standard, and any change now would inevitably render necessary continual
reductions, to the great detriment and inconvenience of the mass of our
people, and with little or no practical benefit, except perhaps to a
small class of scientific and pseudo-scientific men, who can and do amuse
themselves with the fancied uniformity of the mètre.
All our numerous text-books and tables, mechanical and scientific, would
be rendered entirely useless by the change, and this is a serious final
consideration.