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:
|A. - PRACTICAL ELECTRIC UNITS.|
|Total resistance of a circuit.||R|
|Internal resistance of a source of current.||r|
|Resistance of the separate parts of a current.||r, r, etc.|
|Intensity of a current.||C|
|Magnitude of 1 ampere.||A|
|Magnitude of 1 volt.||v|
|Constant of specific induction.||σ|
|Quantity of electricity.||Q|
|Electric work (volt coulomb).||vC|
|Electric effect (volt ampere, watt in one second).||W|
|B. - MAGNETISM.|
|Pole of magnet pointing toward the north.||N|
|The opposite pole.||S|
|Force of a pole, quantity of magnetism.||m|
|Distance of the poles of a magnet.||l|
|Magnetic moment.||M = m.l|
|Intensity of magnetization.||J|
|Intensity of the horizontal component of terrestrial magnetism.||H|
|C. - ELECTRIC MEASUREMENTS.|
|Galvanometer and its resistance.||G|
|Resistance of the shunt of a galvanometer.||s|
|Battery and its internal resistance.||B|
For dynamo machines, the following designations are proposed:
|The machine itself.||D|
|Magnet forming the field.||FM|
|Current indicator (amperemeter).||AM|
|Tension indicator (voltameter).||MV|
|Luminous intensity of a lamp, in candles.||c.p.|
|Resistance of the armature.||R|
|Resistance of the magnet forming the field.||R|
|Resistance of the external circuit.||R|
|Intensity in the armature.||C|
|Intensity in the coils of the magnet.||C|
|Intensity in the external circuit.||C|
|Coefficient of self-induction.||L|
|Coefficient of mutual induction.||L|
A primary battery would be represented as in Fig. 1, and a battery of accumulators as in Fig. 2.
In order to designate incandescent lamps, circles would be used, and stars for arc lamps. A system of incandescent lamps arranged in multiple arc would be represented as in Fig. 3.
Fig. 4 and the formula
R = B + Gs/(G + s) + r
would serve for the total resistance, R, of an electric circuit, upon giving the letters the significations adopted.
Such is, in brief, the present state of the question. The scientific bodies that have taken hold of it have not as yet furnished a fully co-ordinated work on the subject. Let us hope, however, that we shall not have to wait long. The question is of as much interest to scientific men as to practical ones.
A collection of identical symbols would have the advantage of permitting us to abridge explanations in regard to the signification of terms used in mathematical formulas. A simple examination of a formula would suffice to teach us its contents without the aid of tiresome explanatory matter.
But in order that the language shall be precise, it will be necessary for the words always to represent precise ideas that are universally accepted, and for their sense not to depend upon the manner of understanding the idea according to their arrangement in the phrase.
Nothing can be more desirable than that the societies of electricians of all countries shall continue the study of these questions with the desire of coming to a common understanding through a mutual sacrifice of certain preferences and habitudes. - E. Dieudonne, in La Lumiere Electrique.