Aphorism XVIII.
In forming a Terminology, words may be invented when necessary, but they cannot be conveniently borrowed from casual or arbitrary circumstances[48].
[48] I may also refer to Hist. Sc. Id. b. viii. c. ii. sec. 2, for some remarks on Terminology.
It will be recollected that Terminology is a language employed for describing objects, Nomenclature, a body 312 of names of the objects themselves. The names, as was stated in the last maxim, may be arbitrary; but the descriptive terms must be borrowed from words of suitable meaning in the modern or the classical languages. Thus the whole terminology which Linnæus introduced into botany, is founded upon the received use of Latin words, although he defined their meaning so as to make it precise when it was not so, according to Aphorism [V.] But many of the terms were invented by him and other botanists, as Perianth, Nectary, Pericarp; so many, indeed, as to form, along with the others, a considerable language. Many of the terms which are now become familiar were originally invented by writers on botany. Thus the word Petal, for one division of the corolla, was introduced by Fabius Columna. The term Sepal was devised by Necker to express each of the divisions of the calyx. And up to the most recent times, new denominations of parts and conditions of parts have been devised by botanists, when they found them necessary, in order to mark important differences or resemblances. Thus the general Receptacle of the flower, as it is termed by Linnæus, or Torus by Salisbury, is continued into organs which carry the stamina and pistil, or the pistil alone, or the whole flower; this organ has hence been termed[49] Gonophore, Carpophore, and Anthophore, in these cases.
[49] De Candolle’s Th. El. 405.
In like manner when Cuvier had ascertained that the lower jaws of Saurians consisted always of six pieces having definite relations of form and position, he gave names to them, and termed them respectively the Dental, the Angular, the Coronoid, the Articular, the Complementary, and the Opercular Bones.
In all these cases, the descriptive terms thus introduced have been significant in their derivation. An attempt to circulate a perfectly arbitrary word as a means of description would probably be unsuccessful. We have, indeed, some examples approaching to arbitrary designations, in the Wernerian names of colours, 313 which are a part of the terminology of Natural History. Many of these names are borrowed from natural resemblances, as Auricula purple, Apple green, Straw yellow; but the names of others are taken from casual occurrences, mostly, however, such as were already recognized in common language, as Prussian blue, Dutch orange, King’s yellow.
The extension of arbitrary names in scientific terminology is by no means to be encouraged. I may mention a case in which it was very properly avoided. When Mr. Faraday’s researches on Voltaic electricity had led him to perceive the great impropriety of the term poles, as applied to the apparatus, since the processes have not reference to any opposed points, but to two opposite directions of a path, he very suitably wished to substitute for the phrases positive pole and negative pole, two words ending in ode, from ὅδος, a way. A person who did not see the value of our present maxim, that descriptive terms should be descriptive in their origin, might have proposed words perfectly arbitrary, as Alphode, and Betode: or, if he wished to pay a tribute of respect to the discoverers in this department of science, Galvanode and Voltaode, But such words would very justly have been rejected by Mr. Faraday, and would hardly have obtained any general currency among men of science. Zincode and Platinode, terms derived from the metal which, in one modification of the apparatus, forms what was previously termed the pole, are to be avoided, because in their origin too much is casual; and they are not a good basis for derivative terms. The pole at which the zinc is, is the Anode or Cathode, according as it is associated with different metals. Either the Zincode must sometimes mean the pole at which the Zinc is, and at other times that at which the Zinc is not, or else we must have as many names for poles as there are metals. Anode and Cathode, the terms which Mr. Faraday adopted, were free from these objections; for they refer to a natural standard of the direction of the voltaic current, in a manner which, though perhaps not obvious at first sight, is easily understood and 314 retained. Anode and Cathode, the rising and the setting way, are the directions which correspond to east and west in that voltaic current to which we must ascribe terrestrial magnetism. And with these words it was easy to connect Anïon and Cathïon, to designate the opposite elements which are separated and liberated at the two Electrodes.
Aphorism XIX.
The meaning of Technical Terms must be fixed by convention, not by casual reference to the ordinary meaning of words.