We may discourse for some time to come upon the uniformity of electric
language, for universal agreement is far from being established. An
important step toward the unity of this language was taken in 1881 by the
congress of Paris, which rendered the use of the C.G.S. system definitive
and universal. This labor was completed in 1884 by the meeting of a new
congress at Paris, at which a definition of the C.G.S. and practical
units was distinctly decided upon. That the unit of light defined by the
congress has not rapidly come into favor is due to the fact that its
practical realization is not within everybody's reach.
The work of unification should not come to a standstill on so good a
road. How many times in scientific works or in practical applications do
we find the same physical magnitude designated by different names, or
even the use of the same expression to designate entirely different
things!
The result is an increase of difficulties and confusions, not only for
persons not thoroughly initiated into these notions, but also for adepts,
even, in this new branch of the engineer's art. The effects of such
confusion make themselves still further felt in the reading of foreign
publications. Thus, for example, in Germany that part of a dynamo
electric machine that is called in France the _induit_ (armature) is
sometimes styled _anker_, and more rarely _armatur_. The _north pole_ of
a freely suspended magnetized needle is the one that points toward the
geographical north of the earth. In France, and by some English authors,
this pole is called the _south_ one. Among electricians of the same
country, what by one is called _electro-motive force_ is by another
styled _difference of potential_, by a third _tension_, and even
_difference of tension_.
Our confrere Ruhlmann, of the _Elektrotechnische Zeitschrift_, gives a
still more remarkable example yet of such confusion. The word
_polarization_, borrowed from optics, where it has an unequivocal sense,
serves likewise to designate the development of the counter
electro-motive force of galvanic elements, and also that essentially
different condition of badly conducting substances that is brought about
by the simultaneous influence of quantities of opposite electricity.
In Germany, the word _induction_, coupled with the word _wire_, for
example, according to the formation of compound words in that language,
may also have a double meaning, and it is by the sense alone of the
phrase that we learn whether we have to do with an induced wire or an
inducting one. The examples might be multiplied.
At its session of November 5, 1884, the International Society of
Electricians, upon a motion of Mr. Hospitalier, who had made a
communication upon this question, appointed a committee to study it and
report upon it. The English Society of Electricians likewise took the
subject into consideration, and one of its most active and distinguished
members, Mr. Jamieson, presented the result of his labors at the May
session of the society in 1885.
A discussion arose in which the committee of the International Society of
Electricians was invited to take part. The committee was represented by
its secretary, Mr. Hospitalier, who expressed himself in about these
words: "The committee on electric notations presided over by Mr. Blauvelt
has finished a part of its task, that relative to abbreviations,
notations, and symbols. It will soon take up the second part, which
relates to definitions and agreements." He broadly outlined the
committee's ideas as follows:
In all physical magnitudes that are made use of, we have: (1) the
physical magnitude itself, aside from the units that serve to measure it;
(2) the C.G.S. unit that serves to measure such grandeur (granted the
adoption of the C.G.S. system); (3) practical units, which, in general,
have a special name for each kind of magnitude, and are a decimal
multiple or sub-multiple of the C.G.S. unit, except for time and angles;
(4) finally, decimal multiples and sub-multiples of these practical
units, that are in current use.
The committee likewise decided always to adopt a large capital to
designate the physical magnitude; a small capital to designate the C.G.S.
unit, when it has a special name; a "lower case" letter for the
abbreviation of each practical unit; and prefixes, always the same, for
the decimal multiples and sub-multiples of the practical units.
Thus, for example, work would be indicated by the letter W (initial of
the word); the C.G.S. unit is the _erg_, which would be written without
abbreviation, on account of its being short; and the practical units
would be the kilogrammeter (_kgm_), the grammeter (_gm_), etc. The
multiples would be the _meg-erg_, the tonne-meter (_t-m_), etc.
Mr. Jamieson's propositions have been in great part approved. Some
criticisms, however, were made during the course of the discussion, and
it is for this reason that the scheme still remains open to improvements.
The proposed symbols are as follows: