We have borrowed from the Arabians various astronomical terms, as Zenith, Nadir, Azimuth, Almacantar. And these words, which among the Arabians probably belonged to the first class, of appropriated scientific terms, are for us examples of the second class, invented scientific terms; although they differ from most that we have mentioned, in not containing an etymology corresponding to their meaning in any language with which European cultivators of science are generally familiar. Indeed, the distinction of our two classes, though convenient, is in a great measure, casual. Thus most of the words we formerly mentioned, as parallax, horizon, eclipse, though appropriated technical terms among the Greeks, are to us invented technical terms.
In the construction of such terms as we are now considering, those languages have a great advantage which possess a power of forming words by composition. This was eminently the case with the Greek language; and hence most of the ancient terms of science in that language, when their origin is once explained, are clearly understood and easily retained. Of modern European languages, the German possesses the greatest facility of composition; and hence scientific authors in that language are able to invent terms which it is impossible to imitate in the other languages of Europe. Thus Weiss distinguishes his various systems of crystals as zwei-und-zwei-gliedrig, ein-und-zwei-gliedrig, drey-und-drey-gliedrig, &c., (two-and-two-membered, one-and-two-membered, &c.) And Hessel, also a writer on crystallography, speaks of doubly-one-membered edges, four-and-three spaced rays, and the like.
How far the composition of words, in such cases, may be practised in the English language, and the general question, what are the best rules and artifices 264 in such cases, I shall afterwards consider. In the mean time, I may observe that this list of invented technical terms might easily be much enlarged. Thus in harmonics we have the various intervals, as a Fourth, a Fifth, an Octave, (Diatessaron, Diapente, Diapason,) a Comma, which is the difference of a Major and Minor Tone; we have the various Moods or Keys, and the notes of various lengths, as Minims, Breves, Semibreves, Quavers. In chemistry, Gas was at first a technical term invented by Van Helmont, though it has now been almost adopted into common language. I omit many words which will perhaps suggest themselves to the reader, because they belong rather to the next class, which I now proceed to notice.
III. The third class of technical terms consists of such as are constructed by men of science, and involve some theoretical idea in the meaning which their derivation implies. They do not merely describe, like the class last spoken of, but describe with reference to some doctrine or hypothesis which is accepted as a portion of science. Thus latitude and longitude, according to their origin, signify breadth and length; they are used, however, to denote measures of the distance of a place on the earth’s surface from the equator, and from the first meridian, of which distances, one cannot be called length more properly than the other. But this appropriation of these words may be explained by recollecting that the earth, as known to the ancient geographers, was much further extended from east to west than from north to south. The Precession of the equinoxes is a term which implies that the stars are fixed, while the point which is the origin of the measure of celestial longitude moves backward. The Right Ascension of a star is a measure of its position corresponding to terrestrial longitude; this quantity is identical with the angular ascent of the equinoctial point, when the star is in the horizon in a right sphere; that is, a sphere which supposes the spectator to be at the equator. The Oblique Ascension (a term now little used), is derived in like manner from an oblique sphere. The motion of a planet is direct or retrograde, in 265 consequentia (signa), or in antecedentia, in reference to a certain assumed standard direction for celestial motions, namely, the direction opposite to that of the sun’s daily motion, and agreeing with his annual motion among the stars; or with what is much more evident, the moon’s monthly motion. The equation of time is the quantity which must be added to or subtracted from the time marked by the sun, in order to reduce it to a theoretical condition of equable progress. In like manner the equation of the center of the sun or of the moon is the angle which must be added to, or subtracted from, the actual advance of the luminary in the heavens, in order to make its motion equable. Besides the equation of the center of the moon, which represents the first and greatest of her deviations from equable motion, there are many other equations, by the application of which her motion is brought nearer and nearer to perfect uniformity. The second of these equations is called the evection, the third the variation, the fourth the annual equation, The motion of the sun as affected by its inequalities is called his anomaly, which term denotes inequality. In the History of Astronomy, we find that the inequable motions of the sun, moon, and planets were, in a great measure, reduced to rule and system by the Greeks, by the aid of an hypothesis of circles, revolving, and carrying in their motion other circles which also revolved. This hypothesis introduced many technical terms, as deferent, epicycle, eccentric. In like manner, the theories which have more recently taken the place of the theory of epicycles have introduced other technical terms, as the elliptical orbit, the radius vector, and the equable description of areas by this radius, which phrases express the true laws of the planetary motions.
There is no subject on which theoretical views have been so long and so extensively prevalent as astronomy, and therefore no other science in which there are so many technical terms of the kind we are now considering. But in other subjects also, so far as theories have been established, they have been accompanied by the introduction or fixation of technical terms. Thus, as 266 we have seen in the examination of the foundations of mechanics, the terms force and inertia derive their precise meaning from a recognition of the first law of motion; accelerating force and composition of motion involve the second law; moving force, momentum, action and reaction, are expressions which imply the third law. The term vis viva was introduced to express a general property of moving bodies; and other terms have been introduced for like purposes, as impetus by Smeaton, and work done, by other engineers. In the recent writings of several French engineers, the term travail is much employed, to express the work done and the force which does it: this term has been rendered by labouring force. The proposition which was termed the hydrostatic paradox had this name in reference to its violating a supposed law of the action of forces. The verb to gravitate, and the abstract term gravitation, sealed the establishment of Newton’s theory of the solar system.
In some of the sciences, opinions, either false, or disguised in very fantastical imagery, have prevailed; and the terms which have been introduced during the reign of such opinions, bear the impress of the time. Thus in the days of alchemy, the substances with which the operator dealt were personified; and a metal when exhibited pure and free from all admixture was considered as a little king, and was hence called a regulus, a term not yet quite obsolete. In like manner, a substance from which nothing more of any value could be extracted, was dead, and was called a caput mortuum. Quick silver, that is, live silver (argentum vivum), was killed by certain admixtures, and was revived when restored to its pure state.
We find a great number of medical terms which bear the mark of opinions formerly prevalent among physicians; and though these opinions hardly form a part of the progress of science, and were not presented in our History, we may notice some of these terms as examples of the mode in which words involve in their derivation obsolete opinions. Such words as hysterics, hypochondriac, melancholy, cholera, colic, quinsey 267 (squinantia, συνάγχη, a suffocation), megrim, migrane (hemicranium, the middle of the skull), rickets, (rachitis, from ῥάχις, the backbone), palsy, (paralysis, παράλυσις,) apoplexy (ἀποπληξία, a stroke), emrods, (αἱμοῤῥοΐδες, hemorrhoids, a flux of blood), imposthume, (corrupted from aposteme, ἀπόστημα, an abscess), phthisis (φθίσις, consumption), tympanum (τυμπανία, swelling), dropsy (hydropsy, ὕδρωψ,) sciatica, isciatica (ἰσκιαδικὴ, from ἰσκίον, the hip), catarrh (κατάῤῥους, a flowing down), diarrhœa (διαῤῥοία, a flowing through), diabetes (διαβήτης, a passing through), dysentery (δυσεντερία, a disorder of the entrails), arthritic pains (from ἄρθρα, the joints), are names derived from the supposed or real seat and circumstances of the diseases. The word from which the first of the above names is derived (ὑστέρα, the last place,) signifies the womb, according to its order in a certain systematic enumeration of parts. The second word, hypochondriac, means something affecting the viscera below the cartilage of the breastbone, which cartilage is called χόνδρος; melancholy and cholera derive their names from supposed affections of χολὴ, the bile. Colic is that which affects the colon (κῶλον), the largest member of the bowels. A disorder of the eye is called gutta serena (the ‘drop serene’ of Milton), in contradistinction to gutta turbida, in which the impediment to vision is perceptibly opake. Other terms also record the opinions of the ancient anatomists, as duodenum, a certain portion of the intestines, which they estimated as twelve inches long. We might add other allusions, as the tendon of Achilles.
Astrology also supplied a number of words founded upon fanciful opinions; but this study having been expelled from the list of sciences, such words now survive, only so far as they have found a place in common language. Thus men were termed mercurial, martial, jovial, or saturnine, accordingly as their characters were supposed to be determined by the influence of the planets, Mercury, Mars, Jupiter, or Saturn. Other expressions, such as disastrous, ill-starred, exorbitant, lord of the ascendant, and hence ascendancy, influence, 268 a sphere of action, and the like, may serve to show how extensively astrological opinions have affected language, though the doctrine is no longer a recognized science.
The preceding examples will make it manifest that opinions, even of a recondite and complex kind, are often implied in the derivation of words; and thus will show how scientific terms, framed by the cultivators of science, may involve received hypotheses and theories. When terms are thus constructed, they serve not only to convey with ease, but to preserve steadily and to diffuse widely, the opinions which they thus assume. Moreover, they enable the speculator to employ these complex conceptions, the creations of science, and the results of much labour and thought, as readily and familiarly as if they were convictions borrowed at once from the senses. They are thus powerful instruments in enabling philosophers to ascend from one step of induction and generalization to another; and hereby contribute powerfully to the advance of knowledge and truth.
It should be noticed, before we proceed, that the names of natural objects, when they come to be considered as the objects of a science, are selected according to the processes already enumerated. For the most part, the natural historian adopts the common names of animals, plants, minerals, gems, and the like, and only endeavours to secure their steady and consistent application. But many of these names imply some peculiar, often fanciful, belief respecting the object.