16See at theendof these Aphorisms, further illustrations of them from the recent history of Comparative Anatomy and Chemistry.We may, however, remark that Aphorisms III., IV., V., VI., VII., respect peculiarly the Formation of Technical Terms by the Appropriation of Common Words, while the remaining ones apply to the Formation of New Terms.It does not appear possible to lay down a system of rules which may determine and regulate the construction of all technical terms, on all the occasions on which the progress of science makes them necessary or convenient. But if we can collect a few maxims such as have already offered themselves to the minds of philosophers, or such as may be justified by the instances by which we shall illustrate them, these maxims may avail to guide us in doubtful cases, and to prevent our aiming at advantages which are unattainable, or being disturbed by seeming imperfections which are really no evils. I shall therefore state such maxims of this kind as seem most sound and useful.278AphorismIII.In framing scientific terms, the appropriation of old words is preferable to the invention of new ones.Thismaxim is stated by Bacon in his usual striking manner. After mentioningMetaphysic, as one of the divisions of Natural Philosophy, he adds17: ‘Wherein I desire it may be conceived that I use the wordmetaphysicin a different sense from that that is received: and in like manner I doubt not but it will easily appear to men of judgment that in this and other particulars, wheresoever my conception and notion may differ from the ancient, yet I am studious to keep the ancient terms. For, hoping well to deliver myself from mistaking by the order and perspicuous expressing of that I do propound; I am otherwise zealous and affectionate to recede as little from antiquity, either in terms or opinions, as may stand with truth, and the proficience of knowledge, . . . To me, that do desire, as much as lieth in my pen, to ground a sociable intercourse between antiquity and proficience, it seemeth best to keep a way with antiquityusque ad aras; and therefore to retain the ancient terms, though I sometimes alter the uses and definitions; according to the moderate proceeding in civil governments, when, although there be some alteration, yet that holdeth which Tacitus wisely noteth,eadem magistratuum vocabula.’17De Augm.lib. iii. c. iv.We have had before us a sufficient number of examples of scientific terms thus framed; for they formed the first of three classes which we described in the First Aphorism. And we may again remark, that science, when she thus adopts terms which are in common use, always limits and fixes their meaning in a technical manner. We may also repeat here the warning already given respecting terms of this kind, that they are peculiarly liable to mislead readers who279do not take care to understand them in their technical instead of their common signification.Force,momentum,inertia,impetus,vis viva, are terms which are very useful, if we rigorously bear in mind the import which belongs to each of them in the best treatises on Mechanics; but if the reader content himself with conjecturing their meaning from the context, his knowledge will be confused and worthless.In the application of this Third Aphorism, other rules are to be attended to, which I add.AphorismIV.When common words are appropriated as technical terms, their meaning and relations in common use should be retained as far as can conveniently be done.I willstate an example in which this rule seems to be applicable. Mr Davies Gilbert18has recently proposed the termefficiencyto designate the work which a machine, according to the force exerted upon it, is capable of doing; the work being measured by the weight raised, and the space through which it is raised, jointly. The usual term employed among engineers for the work which a machine actually does, measured in the way just stated, isduty. But as there appears to be a little incongruity in calling that workefficiencywhich the machineoughtto do, when we call that workdutywhich it really does, I have proposed to term these two quantitiestheoretical efficiencyandpractical efficiency, ortheoretical dutyandpractical duty19.18Phil. Trans.1827, p. 25.19The termtravailis used by French engineers, to expressefficiencyortheoretical duty. This term has been rendered in English bylabouring force.Since common words are often vague in their meaning, I add as a necessary accompaniment to the Third Aphorism the following:—280AphorismV.When common words are appropriated as technical terms, their meaning may be modified, and must be rigorously fixed.Thisis stated by Bacon in the above extract: ‘to retain the ancient terms, though I sometimesalter the uses and definitions.’ The scientific use of the term is in all cases much more precise than the common use. The loose notions ofvelocityandforcefor instance, which are sufficient for the usual purposes of language, require to be fixed by exact measures when these are made terms in the science of Mechanics.This scientific fixation of the meaning of words is to be looked upon as a matter of convention, although it is in reality often an inevitable result of the progress of science.Momentumis conventionally defined to be the product of the numbers expressing the weight and the velocity; but then, it could be of no use in expressing the laws of motion if it were defined otherwise.Hence it is no valid objection to a scientific term that the word in common language does not mean exactly the same as in its common use. It is no sufficient reason against the use of the termacidfor a class of bodies, that all the substances belonging to this class are not sour. We have seen that atrapeziumis used in geometry for any four-sided figure, though originally it meant a figure with two opposite sides parallel and the two others equal. A certain stratum which lies below the chalk is termed by English geologiststhe green sand. It has sometimes been objected to this denomination that the stratum has very frequently no tinge of green, and that it is often composed of lime with little or no sand. Yet the term is a good technical term in spite of these apparent improprieties; so long as it is carefully applied to that stratum which is geologically equivalent to the greenish sandy bed to which the appellation was originally applied.When it appeared thatgeometrywould have to be employed as much at least about the heavens as the earth, Plato exclaimed against the folly of calling the281science by such a name; since the word signifies ‘earth-measuring;’ yet the wordgeometryhas retained its place and answered its purpose perfectly well up to the present day.But though the meaning of the term may be modified or extended, it must be rigorously fixed when it is appropriated to science. This process is most abundantly exemplified by the terminology of Natural History, and especially of Botany, in which each term has a most precise meaning assigned to it. Thus Linnæus established exact distinctions betweenfasciculus,capitulum,racemus,thyrsus,paniculus,spica,amentum,corymbus,umbella,cyma,verticillus; or, in the language of English Botanists,a tuft,a head,a cluster,a bunch,a panicle,a spike,a catkin,a corymb,an umbel,a cyme,a whorl. And it has since been laid down as a rule20, that each organ ought to have a separate and appropriate name; so that the termleaf, for instance, shall never be applied toa leaflet,a bractea, ora sepalof the calyx.20De Candolle,Theor. El.328.Botanists have not been content with fixing the meaning of their terms by verbal definition, but have also illustrated them by figures, which address the eye. Of these, as excellent modern examples, may be mentioned those which occur in the works of Mirbel21, and Lindley22.21Élémens de Botanique.22Elements of Botany.AphorismVI.When common words are appropriated as technical terms, this must be done so that they are not ambiguous in their application.Anexample will explain this maxim. The conditions of a body, as a solid, a liquid, and an air, have been distinguished as differentformsof the body. But the wordform, as applied to bodies, has other meanings; so that if we were to inquire inwhat formwater exists in a snow-cloud, it might be doubted whether the forms of crystallization were meant, or282the different forms of ice, water, and vapour. Hence I have proposed23to reject the termformin such cases, and to speak of the differentconsistenceof a body in these conditions. The termconsistenceis usually applied to conditions between solid and fluid; and may without effort be extended to those limiting conditions. And though it may appear more harsh to extend the termconsistenceto the state of air, it may be justified by what has been said in speaking of Aphorism V.23Hist. Ind. Sc.b. x. c. ii. sect. 2.I may notice another example of the necessity of avoiding ambiguous words. A philosopher who makes method his study, would naturally be termed amethodist; but unluckily this word is already appropriated to a religious sect: and hence we could hardly venture to speak of Cæsalpinus, Ray, Morison, Rivinus, Tournefort, Linnæus, and their successors, asbotanical methodists. Again, by this maxim, we are almost debarred from using the termphysicianfor a cultivator of the science of physics, because it already signifies a practiser of physic. We might, perhaps, still usephysicianas the equivalent of the Frenchphysicien, in virtue of Aphorism V.; but probably it would be better to form a new word. Thus we may say, that while the Naturalist employs principally the ideas of resemblance and life, thePhysicistproceeds upon the ideas of force, matter, and the properties of matter.Whatever may be thought of this proposal, the maxim which it implies is frequently useful. It is this.AphorismVII.It is better to form new words as technical terms, than to employ old ones in which the last three Aphorisms cannot be complied with.Theprincipal inconvenience attending the employment of new words constructed expressly for the use of science, is the difficulty of effectually introducing them. Readers will not readily take the trouble to learn the meaning of a word, in which the memory is283not assisted by some obvious suggestion connected with the common use of language. When this difficulty is overcome, the new word is better than one merely appropriated; since it is more secure from vagueness and confusion. And in cases where the inconveniences belonging to a scientific use of common words become great and inevitable, a new word must be framed and introduced.The Maxims which belong to the construction of such words will be stated hereafter; but I may notice an instance or two tending to show the necessity of the Maxim now before us.The wordForcehas been appropriated in the science of Mechanics in two senses: as indicating the cause of motion; and again, as expressing certain measures of the effects of this cause, in the phrasesaccelerating forceandmoving force. Hence we might have occasion to speak of the accelerating or moving forceofa certainforce; for instance, if we were to say that the force which governs the motions of the planets resides in the sun; and that the accelerating forceofthisforcevaries only with the distance, but its moving force varies as the product of the mass of the sun and the planet. This is a harsh and incongruous mode of expression; and might have been avoided, if, instead ofaccelerating forceandmoving force, single abstract terms had been introduced by Newton: if, for instance, he had said that the velocity generated in a second measures theaccelerativityof the force which produces it, and the momentum produced in a second measures themotivityof the force.The science which treats of heat has hitherto had no special designation: treatises upon it have generally been termed treatisesOn Heat. But this practice of employing the same term to denote the property and the science which treats of it, is awkward, and often ambiguous. And it is further attended with this inconvenience, that we have no adjective derived from the name of the science, as we have in other cases, when we speak ofacousticalexperiments andopticaltheories. This inconvenience has led various persons to suggest names for the Science of Heat. M. Comte284terms itThermology. In theHistory of the Sciences, I have named itThermotics, which appears to me to agree better with the analogy of the names of other corresponding sciences,AcousticsandOptics.Electricityis in the same condition as Heat; having only one word to express the property and the science. M. Le Comte proposesElectrology: for the same reason as before, I should conceiveElectricsmore agreeable to analogy. The coincidence of the word with the plural of Electric would not give rise to ambiguity; forElectrics, taken as the name of a science, would be singular, likeOpticsandMechanics. But a term offers itself to expresscommonormachine Electrics, which appears worthy of admission, though involving a theoretical view. The received doctrine of the difference between Voltaic and Common Electricity is, that in the former case the fluid must be considered as in motion, in the latter as at rest. The science which treats of the former class of subjects is commonly termedElectrodynamics, which obviously suggests the nameElectrostaticsfor the latter.The subject of the Tides is, in like manner, destitute of any name which designates the science concerned about it. I have ventured to employ the termTidology, having been much engaged in tidological researches.Many persons possess a peculiarity of vision, which disables them from distinguishing certain colours. On examining many such cases, we find that in all such persons the peculiarities are the same; all of them confounding scarlet with green, and pink with blue. Hence they form a class, which, for the convenience of physiologists and others, ought to have a fixed designation. Instead of calling them, as has usually been done, ‘persons having a peculiarity of vision,’ we might take a Greek term implying this meaning, and term themIdiopts.But my business at present is not to speak of the selection of new terms when they are introduced, but to illustrate the maxim that the necessity for their introduction often arises. The construction of new terms will be treated of subsequently.285AphorismVIII.Terms must be constructed and appropriated so as to be fitted to enunciate simply and clearly true general propositions.ThisAphorism may be considered as the fundamental principle and supreme rule of all scientific terminology. It is asserted by Cuvier, speaking of a particular case. Thus he says24of Gmelin, that by placing the lamantin in the genus of morses, and the siren in the genus of eels, he had rendered every general proposition respecting the organization of those genera impossible.24Règne Animal, Introd. viii.The maxim is true of words appropriated as well as invented, and applies equally to the mathematical, chemical, and classificatory sciences. With regard to most of these, and especially the two former classes, it has been abundantly exemplified already, in what has previously been said, and in theHistory of the Sciences. For we have there had to notice many technical terms, with the occasions of their introduction; and all these occasions have involved the intention of expressing in a convenient manner some truth or supposed truth. The terms of Astronomy were adopted for the purpose of stating and reasoning upon the relations of the celestial motions, according to the doctrine of the sphere, and the other laws which were discovered by astronomers. The few technical terms which belong to Mechanics,force,velocity,momentum,inertia, &c., were employed from the first with a view to the expression of the laws of motion and of rest; and were, in the end, limited so as truly and simply to express those laws when they were fully ascertained. In Chemistry, the termphlogistonwas useful, as has been shown in theHistory, in classing together processes which really are of the same nature; and the nomenclature of theoxygentheory was still preferable, because it enabled the chemist to express a still greater number of general truths.286To the connexion here asserted, of theory and nomenclature, we have the testimony of the author of the oxygen theory. In the Preface to hisChemistry, Lavoisier says:—‘Thus while I thought myself employed only in forming a Nomenclature, and while I proposed to myself nothing more than to improve the chemical language, my work transformed itself by degrees, without my being able to prevent it, into a Treatise on the Elements of Chemistry.’ And he then proceeds to show how this happened.It is, however, mainly through the progress of Natural History in modern times, that philosophers have been led to see the importance and necessity of new terms in expressing new truths. Thus Harvey, in the Preface to his work on Generation, says:—‘Be not offended if in setting out the History of the Egg I make use of a new method, and sometimes of unusual terms. For as they which find out a new plantation and new shores call them by names of their own coining, which posterity afterwards accepts and receives, so those that find out new secrets have good title to their compellation. And here, methinks, I hear Galen advising: If we consent in the things, contend not about the words.’The Nomenclature which answers the purposes of Natural History is a Systematic Nomenclature, and will be further considered under the next Aphorism. But we may remark, that the Aphorism now before us governs the use of words, not in science only, but in common language also. Are we to apply the namefishto animals of the whale kind? The answer is determined by our present rule: we are to do so, or not, accordingly as we can best express true propositions. If we are speaking of the internal structure and physiology of the animal, we must not call themfish; for in these respects they deviate widely from fishes: they have warm blood, and produce and suckle their young as land quadrupeds do. But this would not prevent our speaking of thewhale-fishery, and calling such animalsfishon all occasions connected with this employment; for the relations thus arising depend upon the animal’s living in the water, and being caught in a287manner similar to other fishes. A plea that human laws which mention fish do not apply to whales, would be rejected at once by an intelligent judge.[A bituminiferous deposit which occurs amongst the coal measures in the neighbourhood of Edinburgh was used as coal, and called ‘Boghead Cannel Coal.’ But a lawsuit arose upon the question whether this, which geologically was notthe coal, should be regarded in law ascoal. The opinions of chemists and geologists, as well as of lawyers, were discrepant, and a direct decision of the case was evaded.25]25Miller’sChemistry, iii. 98.AphorismIX.In the Classificatory Sciences, a Systematic Nomenclature is necessary; and the System and the Nomenclature are each essential to the utility of the other.Theinconveniences arising from the want of a good Nomenclature were long felt in Botany, and are still felt in Mineralogy. The attempts to remedy them bySynonymiesare very ineffective, for such comparisons of synonyms do not supply a systematic nomenclature; and such a one alone can enable us to state general truths respecting the objects of which the classificatory sciences treat. TheSystemand theNamesought to be introduced together; for the former is a collection of asserted analogies and resemblances, for which the latter provide simple and permanent expressions. Hence it has repeatedly occurred in the progress of Natural History, that good Systems did not take root, or produce any lasting effect among naturalists, because they were not accompanied by a corresponding Nomenclature. In this way, as we have already noticed, the excellent botanical System of Cæsalpinus was without immediate effect upon the science. The work of Willoughby, as Cuvier says26, forms an epoch, and288a happy epoch in Ichthyology; yet because Willoughby had no Nomenclature of his own, and no fixed names for his genera, his immediate influence was not great. Again, in speaking of Schlotheim’s work containing representations of fossil vegetables, M. Adolphe Brongniart observes27that the figures and descriptions are so good, that if the author had established a nomenclature for the objects he describes, his work would have become the basis of all succeeding labours on the subject.26Hist. des Poissons, Pref.27Prodrom. Veg. Foss.p. 3.As additional examples of cases in which the improvement of classification, in recent times, has led philosophers to propose new names, I may mention the termPœcilite, proposed by Mr. Conybeare to designate the group of strata which lies below the oolites and lias, including the new red or variegated sandstone, with the keuper above, and the magnesian limestone below it. Again, the transition districts of our island have recently been reduced to system by Professor Sedgwick and Mr. Murchison; and this step has been marked by the termsCambriansystem, andSiluriansystem, applied to the two great groups of formations which they have respectively examined, and by several other names of the subordinate members of these formations.Thus System and Nomenclature are each essential to the other. Without Nomenclature, the system is not permanently incorporated into the general body of knowledge, and made an instrument of future progress. Without System, the names cannot express general truths, and contain no reason why they should be employed in preference to any other names.This has been generally acknowledged by the most philosophical naturalists of modern times. Thus Linnæus begins that part of his Botanical Philosophy in which names are treated of, by stating that the foundation of botany is twofold,DispositionandDenomination; and he adds this Latin line,Nomina si nescis perit et cognitio rerum.289And Cuvier, in the Preface to hisAnimal Kingdom, explains, in a very striking manner, how the attempt to connect zoology with anatomy led him, at the same time, to reform the classifications, and to correct the nomenclature of preceding zoologists.I have stated that in Mineralogy we are still destitute of a good nomenclature generally current. From what has now been said, it will be seen that it may be very far from easy to supply this defect, since we have, as yet, no generally received system of mineralogical classification. Till we know what are really different species of minerals, and in what larger groups these species can be arranged, so as to have common properties, we shall never obtain a permanent mineralogical nomenclature. ThusLeucocycliteandTesseliteare minerals previously confounded with Apophyllite, which Sir John Herschel and Sir David Brewster distinguished by those names, in consequence of certain optical properties which they exhibit. But are these properties definite distinctions? and are there any external differences corresponding to them? If not, can we consider them as separate species? and if not separate species, ought they to have separate names? In like manner, we might ask ifAugiteandHornblendeare really the same species, as Gustavus Rose has maintained? ifDiallageandHyperstheneare not definitely distinguished, which has been asserted by Kobell? Till such questions are settled, we cannot have a fixed nomenclature in mineralogy. What appears the best course to follow in the present state of the science, I shall consider when we come to speak of the form of technical terms.I may, however, notice here that the main Forms of systematic nomenclature are two:—terms which are produced by combining words of higher and lower generality, as the binary names, consisting of the name of the genus and the species, generally employed by natural historians since the time of Linnæus;—and terms in which some relation of things is indicated by a change in the form of the word, for example, an alteration of its termination, of which kind of290nomenclature we have a conspicuous example in the modern chemistry.AphorismX.New terms and changes of terms, which are not needed in order to express truth, are to be avoided.Asthe Seventh Aphorism asserted that novelties in language may be and ought to be introduced, when they aid the enunciation of truths, we now declare that they are not admissible in any other case. New terms and new systems of terms are not to be introduced, for example, in virtue of their own neatness or symmetry, or other merits, if there is no occasion for their use.I may mention, as an old example of a superfluous attempt of this kind, an occurrence in the history of Astronomy. In 1628 John Bayer and Julius Schiller devised aCœlum Christianum, in which the common names of the planets, &c., were replaced by those of Adam, Moses, and the Patriarchs. The twelve Signs became the twelve Apostles, and the constellations became sacred places and things. Peireskius, who had to pronounce upon the value of this proposal, praised the piety of the inventors, but did not approve, he said28, the design of perverting and confounding whatever of celestial information from the period of the earliest memory is found in books.28Gassendi,Vita Peireskii, 300.Nor are slight anomalies in the existing language of science sufficient ground for a change, if they do not seriously interfere with the expression of our knowledge. Thus Linnæus says29that a fair generic name is not to be exchanged for another though apter one: and30if we separate an old genus into several, we must try to find names for them among the synonyms which describe the old genus. This maxim excludes the restoration of ancient names long disused, no less than the needless invention of new ones. Linnæus291lays down this rule31; and adds, that the botanists of the sixteenth century well nigh ruined botany by their anxiety to recover the ancient names of plants. In like manner Cuvier32laments it as a misfortune, that he has had to introduce many new names; and declares earnestly that he has taken great pains to preserve those of his predecessors.29Phil. Bot.246.30Ib.247.31Phil. Bot.248.32Règne Anim.Pref. xvi.The great bulk which the Synonymy of botany and of mineralogy have attained, shows us that this maxim has not been universally attended to. In these cases, however, the multiplication of different names for the same kind of object has arisen in general from ignorance of the identity of it under different circumstances, or from the want of a system which might assign to it its proper place. But there are other instances, in which the multiplication of names has arisen not from defect, but from excess, of the spirit of system. The love which speculative men bear towards symmetry and completeness is constantly at work, to make them create systems of classification more regular and more perfect than can be verified by the facts: and as good systems are closely connected with a good nomenclature, systems thus erroneous and superfluous lead to a nomenclature which is prejudicial to science. For although such a nomenclature is finally expelled, when it is found not to aid us in expressing the true laws of nature, it may obtain some temporary sway, during which, and even afterwards, it may be a source of much confusion.We have a conspicuous example of such a result in the geological nomenclature of Werner and his school. Thus it was assumed, in Werner’s system, that hisFirst,Second, andThird Flötz Limestone, hisOldandNew Red Sandstone, were universal formations; and geologists looked upon it as their business to detect these strata in other countries. Names were thus assigned to the rocks of various parts of Europe, which created immense perplexity before they were again ejected. The geological terms which now prevail, for292instance, those of Smith, are for the most part not systematic, but are borrowed from accidents, as localities, or popular names; asOxford ClayandCornbrash; and hence they are not liable to be thrust out on a change of system. On the other hand we do not find sufficient reason to accept the system of names of strata proposed by Mr. Conybeare in theIntroduction to the Geology of England and Wales, according to which theCarboniferous Rocksare theMedial Order,—having above them theSupermedial Order(New Red Sand,OolitesandChalk), and above these theSuperior Order(Tertiary Rocks); and again,—having below, theSubmedial Order(theTransition Rocks), and theInferior Order(Mica Slate,Gneiss,Granite). For though these names have long been proposed, it does not appear that they are useful in enunciating geological truths. We may, it would seem, pronounce the same judgment respecting the system of geological names proposed by M. Alexander Brongniart, in hisTableau des Terrains qui composent l’écorce du Globe. He divides these strata into nine classes, which he termsTerrains Alluviens,Lysiens,Pyrogenes,Clysmiens,Yzemiens,Hemilysiens,Agalysiens,Plutoniques,Vulcaniques. These classes are again variously subdivided: thus the Terrains Yzemiens areThalassiques,Pelagiques, andAbyssiques; and the Abyssiques are subdivided intoLias,Keuper,Conchiliens,Pœciliens,Peneens,Rudimentaires,Entritiques,Houillers,CarbonifersandGres Rouge Ancien. Scarcely any amount of new truths would induce geologists to burthen themselves at once with this enormous system of new names: but in fact, it is evident that any portion of truth, which any author can have brought to light, may be conveyed by means of a much simpler apparatus. Such a nomenclature carries its condemnation on its own face.Nearly the same may be said of the systematic nomenclature proposed for mineralogy by Professor Mohs. Even if all his Genera be really natural groups, (a doctrine which we can have no confidence in till they are confirmed by the evidence of chemistry,) there is no293necessity to make so great a change in the received names of minerals. His proceeding in this respect, so different from the temperance of Linnæus and Cuvier, has probably ensured a speedy oblivion to this part of his system. In crystallography, on the other hand, in which Mohs’s improvements have been very valuable, there are several terms introduced by him, asrhombohedron,scalenohedron,hemihedral,systemsof crystallization, which will probably be a permanent portion of the language of science.I may remark, in general, that the only persons who succeed in making great alterations in the language of science, are not those who make names arbitrarily and as an exercise of ingenuity, but those who have much new knowledge to communicate; so that the vehicle is commended to general reception by the value of what it contains. It is only eminent discoverers to whom the authority is conceded of introducing a new system of names; just as it is only the highest authority in the state which has the power of putting a new coinage in circulation.I will here quote some judicious remarks of Mr. Howard, which fall partly under this Aphorism, and partly under some which follow. He had proposed, as names for the kinds of clouds, the following:Cirrus,Cirrocumulus,Cirrostratus,Cumulostratus,Cumulus,Nimbus,Stratus. In an abridgment of his views, given in the Supplement to theEncyclopædia Britannica, English names were proposed as the equivalents of these;Curlcloud,Sondercloud,Wanecloud,Twaincloud,Stackencloud,Raincloud,Fallcloud. Upon these Mr. Howard observes: ‘I mention these, in order to have the opportunity of saying that I do not adopt them. The names for the clouds which I deduced from the Latin, are but seven in number, and very easy to remember. They were intended asarbitrary termsfor thestructureof clouds, and the meaning of them was carefully fixed by a definition. The observer having once made himself master of this, was able to apply the term with correctness, after a little experience, to the subject under all its varieties of form, colour, or position. The294new names, if meant to be another set of arbitrary terms, are superfluous; if intended to convey in themselves an explanation in English, they fail in this, by applying to some part or circumstance only of the definition; thewholeof which must be kept in view to study the subject with success. To take for an example the first of the modifications. The termcirrusvery readily takes an abstract meaning, equally applicable to the rectilinear as to the flexuous forms of the subject. But the name ofcurl-cloudwill not, without some violence to itsobvious sense, acquire this more extensive one: and will therefore be apt to mislead the reader rather than further his progress. Others of these names are as devoid of a meaning obvious to the English reader, as the Latin terms themselves. But the principal objection to English or any other local terms, remains to be stated. They take away from the nomenclature its general advantage of constituting, as far as it goes, an universal language, by means of which the intelligent of every country may convey to each other their ideas without the necessity of translation.’I here adduce these as examples of the arguments against changing an established nomenclature. As grounds of selecting a new one, they may be taken into account hereafter.AphorismXI.Terms which imply theoretical views are admissible, as far as the theory is proved.Itis not unfrequently stated that the circumstances from which the names employed in science borrow their meaning, ought to be facts and not theories. But such a recommendation implies a belief that facts are rigorously distinguished from theories and directly opposed to them; which belief, we have repeatedly seen, is unfounded. When theories are firmly established, they become facts; and names founded on such theoretical views are unexceptionable. If we speak of theminor295axisof Jupiter’sorbit, or of hisdensity, or ofthe angle of refraction, orthe length of an undulationof red light, we assume certain theories; but inasmuch as the theories are now the inevitable interpretation of ascertained facts, we can have no better terms to designate the conceptions thus referred to. And hence the rule which we must follow is, not that our terms must involve no theory, but that they imply the theory only in that sense in which it is the interpretation of the facts.For example, the termpolarizationof light was objected to, as involving a theory. Perhaps the term was at first suggested by conceiving light to consist of particles having poles turned in a particular manner. But among intelligent speculators, the notion of polarization soon reduced itself to the simple conception of opposite properties in opposite positions, which is a bare statement of the fact: and the term being understood to have this meaning, is a perfectly good term, and indeed the best which we can imagine for designating what is intended.I need hardly add the caution, that names involving theoretical views not in accordance with facts are to be rejected. The following instances exemplify both the positive and the negative application of this maxim.The distinction ofprimaryandsecondaryrocks in geology was founded upon a theory; namely, that those which do not contain any organic remains were first deposited, and afterwards, those which contain plants and animals. But this theory was insecure from the first. The difficulty of making the separation which it implied, led to the introduction of a class oftransitionrocks. And the recent researches of geologists lead them to the conclusion, that those rocks which are termedprimary, may be the newest, not the oldest, productions of nature.In order to avoid this incongruity, other terms have been proposed as substitutes for these. Sir C. Lyell remarks33, that granite, gneiss, and the like, form a class296which should be designated by a common name; which name should not be of chronological import. He proposeshypogene, signifying ‘nether-formed;’ and thus he adopts the theory that they have not assumed their present form and structure at the surface, but determines nothing of the period when they were produced.33Princ. Geol.iv. 386.These hypogene rocks, again, he divides into unstratified orplutonic, and altered stratified, ormetamorphic; the latter term implying the hypothesis that the stratified rocks to which it is applied have been altered, by the effect of fire or otherwise, since they were deposited. That fossiliferous strata, in some cases at least, have undergone such a change, is demonstrable from facts34.34Elem. Geol.p. 17.The modern nomenclature of chemistry implies the oxygen theory of chemistry. Hence it has sometimes been objected to. Thus Davy, in speaking of the Lavoisierian nomenclature, makes the following remarks, which, however plausible they may sound, will be found to be utterly erroneous35. ‘Simplicity and precision ought to be the characteristics of a scientific nomenclature: words should signifythings, or theanalogiesof things, and notopinions.... A substance in one age supposed to be simple, in another is proved to be compound, andvice versâ. A theoretical nomenclature is liable to continual alterations:oxygenated muriatic acidis as improper a term asdephlogisticated marine acid. Every school believes itself to be in the right: and if every school assumes to itself the liberty of altering the names of chemical substances in consequence ofnew ideasof their composition, there can be no permanency in the language of the science; it must always be confused and uncertain. Bodies which aresimilarto each other should always be classed together; and there is a presumption that their composition isanalogous.Metals,earths,alkalis, are appropriate names for the bodies they represent, and independent of all speculation: whereasoxides,sulphurets, andmuriatesare terms founded upon opinions of the composition of bodies, some of which have been already found erroneous.297The least dangerous mode of giving a systematic form to a language seems to be to signify the analogies of substances by some common sign affixed to the beginning or the termination of the word. Thus as the metals have been distinguished by a termination inum, asaurum, so their calciform or oxidated state might have been denoted by a termination ina, asaura: and no progress, however great, in the science could render it necessary that such a mode of appellation should be changed.’
16See at theendof these Aphorisms, further illustrations of them from the recent history of Comparative Anatomy and Chemistry.
We may, however, remark that Aphorisms III., IV., V., VI., VII., respect peculiarly the Formation of Technical Terms by the Appropriation of Common Words, while the remaining ones apply to the Formation of New Terms.
It does not appear possible to lay down a system of rules which may determine and regulate the construction of all technical terms, on all the occasions on which the progress of science makes them necessary or convenient. But if we can collect a few maxims such as have already offered themselves to the minds of philosophers, or such as may be justified by the instances by which we shall illustrate them, these maxims may avail to guide us in doubtful cases, and to prevent our aiming at advantages which are unattainable, or being disturbed by seeming imperfections which are really no evils. I shall therefore state such maxims of this kind as seem most sound and useful.278
AphorismIII.
In framing scientific terms, the appropriation of old words is preferable to the invention of new ones.
Thismaxim is stated by Bacon in his usual striking manner. After mentioningMetaphysic, as one of the divisions of Natural Philosophy, he adds17: ‘Wherein I desire it may be conceived that I use the wordmetaphysicin a different sense from that that is received: and in like manner I doubt not but it will easily appear to men of judgment that in this and other particulars, wheresoever my conception and notion may differ from the ancient, yet I am studious to keep the ancient terms. For, hoping well to deliver myself from mistaking by the order and perspicuous expressing of that I do propound; I am otherwise zealous and affectionate to recede as little from antiquity, either in terms or opinions, as may stand with truth, and the proficience of knowledge, . . . To me, that do desire, as much as lieth in my pen, to ground a sociable intercourse between antiquity and proficience, it seemeth best to keep a way with antiquityusque ad aras; and therefore to retain the ancient terms, though I sometimes alter the uses and definitions; according to the moderate proceeding in civil governments, when, although there be some alteration, yet that holdeth which Tacitus wisely noteth,eadem magistratuum vocabula.’
17De Augm.lib. iii. c. iv.
We have had before us a sufficient number of examples of scientific terms thus framed; for they formed the first of three classes which we described in the First Aphorism. And we may again remark, that science, when she thus adopts terms which are in common use, always limits and fixes their meaning in a technical manner. We may also repeat here the warning already given respecting terms of this kind, that they are peculiarly liable to mislead readers who279do not take care to understand them in their technical instead of their common signification.Force,momentum,inertia,impetus,vis viva, are terms which are very useful, if we rigorously bear in mind the import which belongs to each of them in the best treatises on Mechanics; but if the reader content himself with conjecturing their meaning from the context, his knowledge will be confused and worthless.
In the application of this Third Aphorism, other rules are to be attended to, which I add.
AphorismIV.
When common words are appropriated as technical terms, their meaning and relations in common use should be retained as far as can conveniently be done.
I willstate an example in which this rule seems to be applicable. Mr Davies Gilbert18has recently proposed the termefficiencyto designate the work which a machine, according to the force exerted upon it, is capable of doing; the work being measured by the weight raised, and the space through which it is raised, jointly. The usual term employed among engineers for the work which a machine actually does, measured in the way just stated, isduty. But as there appears to be a little incongruity in calling that workefficiencywhich the machineoughtto do, when we call that workdutywhich it really does, I have proposed to term these two quantitiestheoretical efficiencyandpractical efficiency, ortheoretical dutyandpractical duty19.
18Phil. Trans.1827, p. 25.
19The termtravailis used by French engineers, to expressefficiencyortheoretical duty. This term has been rendered in English bylabouring force.
Since common words are often vague in their meaning, I add as a necessary accompaniment to the Third Aphorism the following:—280
AphorismV.
When common words are appropriated as technical terms, their meaning may be modified, and must be rigorously fixed.
Thisis stated by Bacon in the above extract: ‘to retain the ancient terms, though I sometimesalter the uses and definitions.’ The scientific use of the term is in all cases much more precise than the common use. The loose notions ofvelocityandforcefor instance, which are sufficient for the usual purposes of language, require to be fixed by exact measures when these are made terms in the science of Mechanics.
This scientific fixation of the meaning of words is to be looked upon as a matter of convention, although it is in reality often an inevitable result of the progress of science.Momentumis conventionally defined to be the product of the numbers expressing the weight and the velocity; but then, it could be of no use in expressing the laws of motion if it were defined otherwise.
Hence it is no valid objection to a scientific term that the word in common language does not mean exactly the same as in its common use. It is no sufficient reason against the use of the termacidfor a class of bodies, that all the substances belonging to this class are not sour. We have seen that atrapeziumis used in geometry for any four-sided figure, though originally it meant a figure with two opposite sides parallel and the two others equal. A certain stratum which lies below the chalk is termed by English geologiststhe green sand. It has sometimes been objected to this denomination that the stratum has very frequently no tinge of green, and that it is often composed of lime with little or no sand. Yet the term is a good technical term in spite of these apparent improprieties; so long as it is carefully applied to that stratum which is geologically equivalent to the greenish sandy bed to which the appellation was originally applied.
When it appeared thatgeometrywould have to be employed as much at least about the heavens as the earth, Plato exclaimed against the folly of calling the281science by such a name; since the word signifies ‘earth-measuring;’ yet the wordgeometryhas retained its place and answered its purpose perfectly well up to the present day.
But though the meaning of the term may be modified or extended, it must be rigorously fixed when it is appropriated to science. This process is most abundantly exemplified by the terminology of Natural History, and especially of Botany, in which each term has a most precise meaning assigned to it. Thus Linnæus established exact distinctions betweenfasciculus,capitulum,racemus,thyrsus,paniculus,spica,amentum,corymbus,umbella,cyma,verticillus; or, in the language of English Botanists,a tuft,a head,a cluster,a bunch,a panicle,a spike,a catkin,a corymb,an umbel,a cyme,a whorl. And it has since been laid down as a rule20, that each organ ought to have a separate and appropriate name; so that the termleaf, for instance, shall never be applied toa leaflet,a bractea, ora sepalof the calyx.
20De Candolle,Theor. El.328.
Botanists have not been content with fixing the meaning of their terms by verbal definition, but have also illustrated them by figures, which address the eye. Of these, as excellent modern examples, may be mentioned those which occur in the works of Mirbel21, and Lindley22.
21Élémens de Botanique.
22Elements of Botany.
AphorismVI.
When common words are appropriated as technical terms, this must be done so that they are not ambiguous in their application.
Anexample will explain this maxim. The conditions of a body, as a solid, a liquid, and an air, have been distinguished as differentformsof the body. But the wordform, as applied to bodies, has other meanings; so that if we were to inquire inwhat formwater exists in a snow-cloud, it might be doubted whether the forms of crystallization were meant, or282the different forms of ice, water, and vapour. Hence I have proposed23to reject the termformin such cases, and to speak of the differentconsistenceof a body in these conditions. The termconsistenceis usually applied to conditions between solid and fluid; and may without effort be extended to those limiting conditions. And though it may appear more harsh to extend the termconsistenceto the state of air, it may be justified by what has been said in speaking of Aphorism V.
23Hist. Ind. Sc.b. x. c. ii. sect. 2.
I may notice another example of the necessity of avoiding ambiguous words. A philosopher who makes method his study, would naturally be termed amethodist; but unluckily this word is already appropriated to a religious sect: and hence we could hardly venture to speak of Cæsalpinus, Ray, Morison, Rivinus, Tournefort, Linnæus, and their successors, asbotanical methodists. Again, by this maxim, we are almost debarred from using the termphysicianfor a cultivator of the science of physics, because it already signifies a practiser of physic. We might, perhaps, still usephysicianas the equivalent of the Frenchphysicien, in virtue of Aphorism V.; but probably it would be better to form a new word. Thus we may say, that while the Naturalist employs principally the ideas of resemblance and life, thePhysicistproceeds upon the ideas of force, matter, and the properties of matter.
Whatever may be thought of this proposal, the maxim which it implies is frequently useful. It is this.
AphorismVII.
It is better to form new words as technical terms, than to employ old ones in which the last three Aphorisms cannot be complied with.
Theprincipal inconvenience attending the employment of new words constructed expressly for the use of science, is the difficulty of effectually introducing them. Readers will not readily take the trouble to learn the meaning of a word, in which the memory is283not assisted by some obvious suggestion connected with the common use of language. When this difficulty is overcome, the new word is better than one merely appropriated; since it is more secure from vagueness and confusion. And in cases where the inconveniences belonging to a scientific use of common words become great and inevitable, a new word must be framed and introduced.
The Maxims which belong to the construction of such words will be stated hereafter; but I may notice an instance or two tending to show the necessity of the Maxim now before us.
The wordForcehas been appropriated in the science of Mechanics in two senses: as indicating the cause of motion; and again, as expressing certain measures of the effects of this cause, in the phrasesaccelerating forceandmoving force. Hence we might have occasion to speak of the accelerating or moving forceofa certainforce; for instance, if we were to say that the force which governs the motions of the planets resides in the sun; and that the accelerating forceofthisforcevaries only with the distance, but its moving force varies as the product of the mass of the sun and the planet. This is a harsh and incongruous mode of expression; and might have been avoided, if, instead ofaccelerating forceandmoving force, single abstract terms had been introduced by Newton: if, for instance, he had said that the velocity generated in a second measures theaccelerativityof the force which produces it, and the momentum produced in a second measures themotivityof the force.
The science which treats of heat has hitherto had no special designation: treatises upon it have generally been termed treatisesOn Heat. But this practice of employing the same term to denote the property and the science which treats of it, is awkward, and often ambiguous. And it is further attended with this inconvenience, that we have no adjective derived from the name of the science, as we have in other cases, when we speak ofacousticalexperiments andopticaltheories. This inconvenience has led various persons to suggest names for the Science of Heat. M. Comte284terms itThermology. In theHistory of the Sciences, I have named itThermotics, which appears to me to agree better with the analogy of the names of other corresponding sciences,AcousticsandOptics.Electricityis in the same condition as Heat; having only one word to express the property and the science. M. Le Comte proposesElectrology: for the same reason as before, I should conceiveElectricsmore agreeable to analogy. The coincidence of the word with the plural of Electric would not give rise to ambiguity; forElectrics, taken as the name of a science, would be singular, likeOpticsandMechanics. But a term offers itself to expresscommonormachine Electrics, which appears worthy of admission, though involving a theoretical view. The received doctrine of the difference between Voltaic and Common Electricity is, that in the former case the fluid must be considered as in motion, in the latter as at rest. The science which treats of the former class of subjects is commonly termedElectrodynamics, which obviously suggests the nameElectrostaticsfor the latter.
The subject of the Tides is, in like manner, destitute of any name which designates the science concerned about it. I have ventured to employ the termTidology, having been much engaged in tidological researches.
Many persons possess a peculiarity of vision, which disables them from distinguishing certain colours. On examining many such cases, we find that in all such persons the peculiarities are the same; all of them confounding scarlet with green, and pink with blue. Hence they form a class, which, for the convenience of physiologists and others, ought to have a fixed designation. Instead of calling them, as has usually been done, ‘persons having a peculiarity of vision,’ we might take a Greek term implying this meaning, and term themIdiopts.
But my business at present is not to speak of the selection of new terms when they are introduced, but to illustrate the maxim that the necessity for their introduction often arises. The construction of new terms will be treated of subsequently.285
AphorismVIII.
Terms must be constructed and appropriated so as to be fitted to enunciate simply and clearly true general propositions.
ThisAphorism may be considered as the fundamental principle and supreme rule of all scientific terminology. It is asserted by Cuvier, speaking of a particular case. Thus he says24of Gmelin, that by placing the lamantin in the genus of morses, and the siren in the genus of eels, he had rendered every general proposition respecting the organization of those genera impossible.
24Règne Animal, Introd. viii.
The maxim is true of words appropriated as well as invented, and applies equally to the mathematical, chemical, and classificatory sciences. With regard to most of these, and especially the two former classes, it has been abundantly exemplified already, in what has previously been said, and in theHistory of the Sciences. For we have there had to notice many technical terms, with the occasions of their introduction; and all these occasions have involved the intention of expressing in a convenient manner some truth or supposed truth. The terms of Astronomy were adopted for the purpose of stating and reasoning upon the relations of the celestial motions, according to the doctrine of the sphere, and the other laws which were discovered by astronomers. The few technical terms which belong to Mechanics,force,velocity,momentum,inertia, &c., were employed from the first with a view to the expression of the laws of motion and of rest; and were, in the end, limited so as truly and simply to express those laws when they were fully ascertained. In Chemistry, the termphlogistonwas useful, as has been shown in theHistory, in classing together processes which really are of the same nature; and the nomenclature of theoxygentheory was still preferable, because it enabled the chemist to express a still greater number of general truths.286
To the connexion here asserted, of theory and nomenclature, we have the testimony of the author of the oxygen theory. In the Preface to hisChemistry, Lavoisier says:—‘Thus while I thought myself employed only in forming a Nomenclature, and while I proposed to myself nothing more than to improve the chemical language, my work transformed itself by degrees, without my being able to prevent it, into a Treatise on the Elements of Chemistry.’ And he then proceeds to show how this happened.
It is, however, mainly through the progress of Natural History in modern times, that philosophers have been led to see the importance and necessity of new terms in expressing new truths. Thus Harvey, in the Preface to his work on Generation, says:—‘Be not offended if in setting out the History of the Egg I make use of a new method, and sometimes of unusual terms. For as they which find out a new plantation and new shores call them by names of their own coining, which posterity afterwards accepts and receives, so those that find out new secrets have good title to their compellation. And here, methinks, I hear Galen advising: If we consent in the things, contend not about the words.’
The Nomenclature which answers the purposes of Natural History is a Systematic Nomenclature, and will be further considered under the next Aphorism. But we may remark, that the Aphorism now before us governs the use of words, not in science only, but in common language also. Are we to apply the namefishto animals of the whale kind? The answer is determined by our present rule: we are to do so, or not, accordingly as we can best express true propositions. If we are speaking of the internal structure and physiology of the animal, we must not call themfish; for in these respects they deviate widely from fishes: they have warm blood, and produce and suckle their young as land quadrupeds do. But this would not prevent our speaking of thewhale-fishery, and calling such animalsfishon all occasions connected with this employment; for the relations thus arising depend upon the animal’s living in the water, and being caught in a287manner similar to other fishes. A plea that human laws which mention fish do not apply to whales, would be rejected at once by an intelligent judge.
[A bituminiferous deposit which occurs amongst the coal measures in the neighbourhood of Edinburgh was used as coal, and called ‘Boghead Cannel Coal.’ But a lawsuit arose upon the question whether this, which geologically was notthe coal, should be regarded in law ascoal. The opinions of chemists and geologists, as well as of lawyers, were discrepant, and a direct decision of the case was evaded.25]
25Miller’sChemistry, iii. 98.
AphorismIX.
In the Classificatory Sciences, a Systematic Nomenclature is necessary; and the System and the Nomenclature are each essential to the utility of the other.
Theinconveniences arising from the want of a good Nomenclature were long felt in Botany, and are still felt in Mineralogy. The attempts to remedy them bySynonymiesare very ineffective, for such comparisons of synonyms do not supply a systematic nomenclature; and such a one alone can enable us to state general truths respecting the objects of which the classificatory sciences treat. TheSystemand theNamesought to be introduced together; for the former is a collection of asserted analogies and resemblances, for which the latter provide simple and permanent expressions. Hence it has repeatedly occurred in the progress of Natural History, that good Systems did not take root, or produce any lasting effect among naturalists, because they were not accompanied by a corresponding Nomenclature. In this way, as we have already noticed, the excellent botanical System of Cæsalpinus was without immediate effect upon the science. The work of Willoughby, as Cuvier says26, forms an epoch, and288a happy epoch in Ichthyology; yet because Willoughby had no Nomenclature of his own, and no fixed names for his genera, his immediate influence was not great. Again, in speaking of Schlotheim’s work containing representations of fossil vegetables, M. Adolphe Brongniart observes27that the figures and descriptions are so good, that if the author had established a nomenclature for the objects he describes, his work would have become the basis of all succeeding labours on the subject.
26Hist. des Poissons, Pref.
27Prodrom. Veg. Foss.p. 3.
As additional examples of cases in which the improvement of classification, in recent times, has led philosophers to propose new names, I may mention the termPœcilite, proposed by Mr. Conybeare to designate the group of strata which lies below the oolites and lias, including the new red or variegated sandstone, with the keuper above, and the magnesian limestone below it. Again, the transition districts of our island have recently been reduced to system by Professor Sedgwick and Mr. Murchison; and this step has been marked by the termsCambriansystem, andSiluriansystem, applied to the two great groups of formations which they have respectively examined, and by several other names of the subordinate members of these formations.
Thus System and Nomenclature are each essential to the other. Without Nomenclature, the system is not permanently incorporated into the general body of knowledge, and made an instrument of future progress. Without System, the names cannot express general truths, and contain no reason why they should be employed in preference to any other names.
This has been generally acknowledged by the most philosophical naturalists of modern times. Thus Linnæus begins that part of his Botanical Philosophy in which names are treated of, by stating that the foundation of botany is twofold,DispositionandDenomination; and he adds this Latin line,
Nomina si nescis perit et cognitio rerum.289
And Cuvier, in the Preface to hisAnimal Kingdom, explains, in a very striking manner, how the attempt to connect zoology with anatomy led him, at the same time, to reform the classifications, and to correct the nomenclature of preceding zoologists.
I have stated that in Mineralogy we are still destitute of a good nomenclature generally current. From what has now been said, it will be seen that it may be very far from easy to supply this defect, since we have, as yet, no generally received system of mineralogical classification. Till we know what are really different species of minerals, and in what larger groups these species can be arranged, so as to have common properties, we shall never obtain a permanent mineralogical nomenclature. ThusLeucocycliteandTesseliteare minerals previously confounded with Apophyllite, which Sir John Herschel and Sir David Brewster distinguished by those names, in consequence of certain optical properties which they exhibit. But are these properties definite distinctions? and are there any external differences corresponding to them? If not, can we consider them as separate species? and if not separate species, ought they to have separate names? In like manner, we might ask ifAugiteandHornblendeare really the same species, as Gustavus Rose has maintained? ifDiallageandHyperstheneare not definitely distinguished, which has been asserted by Kobell? Till such questions are settled, we cannot have a fixed nomenclature in mineralogy. What appears the best course to follow in the present state of the science, I shall consider when we come to speak of the form of technical terms.
I may, however, notice here that the main Forms of systematic nomenclature are two:—terms which are produced by combining words of higher and lower generality, as the binary names, consisting of the name of the genus and the species, generally employed by natural historians since the time of Linnæus;—and terms in which some relation of things is indicated by a change in the form of the word, for example, an alteration of its termination, of which kind of290nomenclature we have a conspicuous example in the modern chemistry.
AphorismX.
New terms and changes of terms, which are not needed in order to express truth, are to be avoided.
Asthe Seventh Aphorism asserted that novelties in language may be and ought to be introduced, when they aid the enunciation of truths, we now declare that they are not admissible in any other case. New terms and new systems of terms are not to be introduced, for example, in virtue of their own neatness or symmetry, or other merits, if there is no occasion for their use.
I may mention, as an old example of a superfluous attempt of this kind, an occurrence in the history of Astronomy. In 1628 John Bayer and Julius Schiller devised aCœlum Christianum, in which the common names of the planets, &c., were replaced by those of Adam, Moses, and the Patriarchs. The twelve Signs became the twelve Apostles, and the constellations became sacred places and things. Peireskius, who had to pronounce upon the value of this proposal, praised the piety of the inventors, but did not approve, he said28, the design of perverting and confounding whatever of celestial information from the period of the earliest memory is found in books.
28Gassendi,Vita Peireskii, 300.
Nor are slight anomalies in the existing language of science sufficient ground for a change, if they do not seriously interfere with the expression of our knowledge. Thus Linnæus says29that a fair generic name is not to be exchanged for another though apter one: and30if we separate an old genus into several, we must try to find names for them among the synonyms which describe the old genus. This maxim excludes the restoration of ancient names long disused, no less than the needless invention of new ones. Linnæus291lays down this rule31; and adds, that the botanists of the sixteenth century well nigh ruined botany by their anxiety to recover the ancient names of plants. In like manner Cuvier32laments it as a misfortune, that he has had to introduce many new names; and declares earnestly that he has taken great pains to preserve those of his predecessors.
29Phil. Bot.246.
30Ib.247.
31Phil. Bot.248.
32Règne Anim.Pref. xvi.
The great bulk which the Synonymy of botany and of mineralogy have attained, shows us that this maxim has not been universally attended to. In these cases, however, the multiplication of different names for the same kind of object has arisen in general from ignorance of the identity of it under different circumstances, or from the want of a system which might assign to it its proper place. But there are other instances, in which the multiplication of names has arisen not from defect, but from excess, of the spirit of system. The love which speculative men bear towards symmetry and completeness is constantly at work, to make them create systems of classification more regular and more perfect than can be verified by the facts: and as good systems are closely connected with a good nomenclature, systems thus erroneous and superfluous lead to a nomenclature which is prejudicial to science. For although such a nomenclature is finally expelled, when it is found not to aid us in expressing the true laws of nature, it may obtain some temporary sway, during which, and even afterwards, it may be a source of much confusion.
We have a conspicuous example of such a result in the geological nomenclature of Werner and his school. Thus it was assumed, in Werner’s system, that hisFirst,Second, andThird Flötz Limestone, hisOldandNew Red Sandstone, were universal formations; and geologists looked upon it as their business to detect these strata in other countries. Names were thus assigned to the rocks of various parts of Europe, which created immense perplexity before they were again ejected. The geological terms which now prevail, for292instance, those of Smith, are for the most part not systematic, but are borrowed from accidents, as localities, or popular names; asOxford ClayandCornbrash; and hence they are not liable to be thrust out on a change of system. On the other hand we do not find sufficient reason to accept the system of names of strata proposed by Mr. Conybeare in theIntroduction to the Geology of England and Wales, according to which theCarboniferous Rocksare theMedial Order,—having above them theSupermedial Order(New Red Sand,OolitesandChalk), and above these theSuperior Order(Tertiary Rocks); and again,—having below, theSubmedial Order(theTransition Rocks), and theInferior Order(Mica Slate,Gneiss,Granite). For though these names have long been proposed, it does not appear that they are useful in enunciating geological truths. We may, it would seem, pronounce the same judgment respecting the system of geological names proposed by M. Alexander Brongniart, in hisTableau des Terrains qui composent l’écorce du Globe. He divides these strata into nine classes, which he termsTerrains Alluviens,Lysiens,Pyrogenes,Clysmiens,Yzemiens,Hemilysiens,Agalysiens,Plutoniques,Vulcaniques. These classes are again variously subdivided: thus the Terrains Yzemiens areThalassiques,Pelagiques, andAbyssiques; and the Abyssiques are subdivided intoLias,Keuper,Conchiliens,Pœciliens,Peneens,Rudimentaires,Entritiques,Houillers,CarbonifersandGres Rouge Ancien. Scarcely any amount of new truths would induce geologists to burthen themselves at once with this enormous system of new names: but in fact, it is evident that any portion of truth, which any author can have brought to light, may be conveyed by means of a much simpler apparatus. Such a nomenclature carries its condemnation on its own face.
Nearly the same may be said of the systematic nomenclature proposed for mineralogy by Professor Mohs. Even if all his Genera be really natural groups, (a doctrine which we can have no confidence in till they are confirmed by the evidence of chemistry,) there is no293necessity to make so great a change in the received names of minerals. His proceeding in this respect, so different from the temperance of Linnæus and Cuvier, has probably ensured a speedy oblivion to this part of his system. In crystallography, on the other hand, in which Mohs’s improvements have been very valuable, there are several terms introduced by him, asrhombohedron,scalenohedron,hemihedral,systemsof crystallization, which will probably be a permanent portion of the language of science.
I may remark, in general, that the only persons who succeed in making great alterations in the language of science, are not those who make names arbitrarily and as an exercise of ingenuity, but those who have much new knowledge to communicate; so that the vehicle is commended to general reception by the value of what it contains. It is only eminent discoverers to whom the authority is conceded of introducing a new system of names; just as it is only the highest authority in the state which has the power of putting a new coinage in circulation.
I will here quote some judicious remarks of Mr. Howard, which fall partly under this Aphorism, and partly under some which follow. He had proposed, as names for the kinds of clouds, the following:Cirrus,Cirrocumulus,Cirrostratus,Cumulostratus,Cumulus,Nimbus,Stratus. In an abridgment of his views, given in the Supplement to theEncyclopædia Britannica, English names were proposed as the equivalents of these;Curlcloud,Sondercloud,Wanecloud,Twaincloud,Stackencloud,Raincloud,Fallcloud. Upon these Mr. Howard observes: ‘I mention these, in order to have the opportunity of saying that I do not adopt them. The names for the clouds which I deduced from the Latin, are but seven in number, and very easy to remember. They were intended asarbitrary termsfor thestructureof clouds, and the meaning of them was carefully fixed by a definition. The observer having once made himself master of this, was able to apply the term with correctness, after a little experience, to the subject under all its varieties of form, colour, or position. The294new names, if meant to be another set of arbitrary terms, are superfluous; if intended to convey in themselves an explanation in English, they fail in this, by applying to some part or circumstance only of the definition; thewholeof which must be kept in view to study the subject with success. To take for an example the first of the modifications. The termcirrusvery readily takes an abstract meaning, equally applicable to the rectilinear as to the flexuous forms of the subject. But the name ofcurl-cloudwill not, without some violence to itsobvious sense, acquire this more extensive one: and will therefore be apt to mislead the reader rather than further his progress. Others of these names are as devoid of a meaning obvious to the English reader, as the Latin terms themselves. But the principal objection to English or any other local terms, remains to be stated. They take away from the nomenclature its general advantage of constituting, as far as it goes, an universal language, by means of which the intelligent of every country may convey to each other their ideas without the necessity of translation.’
I here adduce these as examples of the arguments against changing an established nomenclature. As grounds of selecting a new one, they may be taken into account hereafter.
AphorismXI.
Terms which imply theoretical views are admissible, as far as the theory is proved.
Itis not unfrequently stated that the circumstances from which the names employed in science borrow their meaning, ought to be facts and not theories. But such a recommendation implies a belief that facts are rigorously distinguished from theories and directly opposed to them; which belief, we have repeatedly seen, is unfounded. When theories are firmly established, they become facts; and names founded on such theoretical views are unexceptionable. If we speak of theminor295axisof Jupiter’sorbit, or of hisdensity, or ofthe angle of refraction, orthe length of an undulationof red light, we assume certain theories; but inasmuch as the theories are now the inevitable interpretation of ascertained facts, we can have no better terms to designate the conceptions thus referred to. And hence the rule which we must follow is, not that our terms must involve no theory, but that they imply the theory only in that sense in which it is the interpretation of the facts.
For example, the termpolarizationof light was objected to, as involving a theory. Perhaps the term was at first suggested by conceiving light to consist of particles having poles turned in a particular manner. But among intelligent speculators, the notion of polarization soon reduced itself to the simple conception of opposite properties in opposite positions, which is a bare statement of the fact: and the term being understood to have this meaning, is a perfectly good term, and indeed the best which we can imagine for designating what is intended.
I need hardly add the caution, that names involving theoretical views not in accordance with facts are to be rejected. The following instances exemplify both the positive and the negative application of this maxim.
The distinction ofprimaryandsecondaryrocks in geology was founded upon a theory; namely, that those which do not contain any organic remains were first deposited, and afterwards, those which contain plants and animals. But this theory was insecure from the first. The difficulty of making the separation which it implied, led to the introduction of a class oftransitionrocks. And the recent researches of geologists lead them to the conclusion, that those rocks which are termedprimary, may be the newest, not the oldest, productions of nature.
In order to avoid this incongruity, other terms have been proposed as substitutes for these. Sir C. Lyell remarks33, that granite, gneiss, and the like, form a class296which should be designated by a common name; which name should not be of chronological import. He proposeshypogene, signifying ‘nether-formed;’ and thus he adopts the theory that they have not assumed their present form and structure at the surface, but determines nothing of the period when they were produced.
33Princ. Geol.iv. 386.
These hypogene rocks, again, he divides into unstratified orplutonic, and altered stratified, ormetamorphic; the latter term implying the hypothesis that the stratified rocks to which it is applied have been altered, by the effect of fire or otherwise, since they were deposited. That fossiliferous strata, in some cases at least, have undergone such a change, is demonstrable from facts34.
34Elem. Geol.p. 17.
The modern nomenclature of chemistry implies the oxygen theory of chemistry. Hence it has sometimes been objected to. Thus Davy, in speaking of the Lavoisierian nomenclature, makes the following remarks, which, however plausible they may sound, will be found to be utterly erroneous35. ‘Simplicity and precision ought to be the characteristics of a scientific nomenclature: words should signifythings, or theanalogiesof things, and notopinions.... A substance in one age supposed to be simple, in another is proved to be compound, andvice versâ. A theoretical nomenclature is liable to continual alterations:oxygenated muriatic acidis as improper a term asdephlogisticated marine acid. Every school believes itself to be in the right: and if every school assumes to itself the liberty of altering the names of chemical substances in consequence ofnew ideasof their composition, there can be no permanency in the language of the science; it must always be confused and uncertain. Bodies which aresimilarto each other should always be classed together; and there is a presumption that their composition isanalogous.Metals,earths,alkalis, are appropriate names for the bodies they represent, and independent of all speculation: whereasoxides,sulphurets, andmuriatesare terms founded upon opinions of the composition of bodies, some of which have been already found erroneous.297The least dangerous mode of giving a systematic form to a language seems to be to signify the analogies of substances by some common sign affixed to the beginning or the termination of the word. Thus as the metals have been distinguished by a termination inum, asaurum, so their calciform or oxidated state might have been denoted by a termination ina, asaura: and no progress, however great, in the science could render it necessary that such a mode of appellation should be changed.’