Popular Science Monthly/Volume 82/March 1913/The Language of Meteorology

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THE LANGUAGE OF METEOROLOGY
By CHARLES FITZHUGH TALMAN,

U. S. WEATHER BUREAU

IN discussing the vocabulary of any branch of science one is embarrassed by the fact that scientific language in general is a neglected subject. The principles of scientific terminology and nomenclature (on the etymological side) are not, to my knowledge, taught in modern curricula; their formal exposition belongs to the scholarly literature of a past generation; and the writings of our contemporaries bear evidence of the fact that philology does not now enter to so large an extent as formerly into the equipment of the average man of science.

The student of to-day is, as a rule, left to make his own generalizations on this subject from the transformations in the technical vocabulary that happens to come under his observation; and his inductions suffer in proportion as these transformations become less orderly. When he arrives at the creative stage, and is called upon to label his contributions to knowledge, he is apt to still further increase the disorder of the language; and thus an interaction is going on that would speedily lead to chaos, if it were not checked by powerful though unrecognized laws governing the development of human speech—a pervasive "Sprachgefühl" that saves the language from falling into rapid ruin, though it can not protect it from gradual deterioration.

The fact that the underlying principles of terminology and nomenclature are not, to say the least, clearly formulated in the minds of most men of science makes it desirable, in discussing a particular group of technical terms or names, to begin far back of one's subject—just as it is desirable for a newspaper writer on Halley's comet to begin by enlightening the public in regard to the heavenly bodies in general. However, it is not practicable to follow such a plan within the limits of a brief paper. In the present case I shall cut the Gordian knot by simply referring my readers to the two statements of fundamental principles that I have myself found most illuminating—viz., the fourth book of William Whewel's "Novum Organon Renovatum" and Dr. Lereboullet's article "Etymologie" in the "Dictionnaire encyclopédique des sciences médicales"—and proceed at once to a discussion of some salient features of the language of meteorology.

One curious fact about this language is that a considerable part of it is unknown to meteorologists. Hundreds of useful terms have been introduced to fill the gaps in its vocabulary—some highly felicitous, others at least tolerable—only to sink into speedy oblivion, leaving their places unfilled. Take, for example, the names of the isograms—and the name "isogram" itself. The latter, denoting a line that represents equality of some physical condition on a map or diagram (the isotherm and the isobar being the most familiar examples, is a convenient generic term, the need of which must have been often felt long before it was invented, in the year 1889, by Francis Galton. Yet to this day it is unknown to most meteorological writers, who continue to use an awkward periphrasis to express this every-day idea.

Several meteorologists have drawn lines connecting places of equal evaporation; very few have ventured to give these lines a name. There is no inconvenience in referring once or twice in a scientific memoir to a "line of equal evaporation." Suppose, however, one needs to mention the same thing fifty times. One is almost driven to the necessity of substituting a single word for this long phrase; and thus certain writers have, in fact, coined the terms "isoatmic line" and "isothyme"; but neither of these has gained currency in the habitual vocabulary of meteorologists.

In all, some eighty meteorological isograms have been named; but of their names less than a score are generally familiar, and many are almost completely forgotten.

During the last two or three years the recognition of the importance of the "barometric tendency" in weather forecasting has made us tolerably familiar with the "isallobar"; but what of the "isallotherm"? Lines of equal temperature-change have been drawn on forecast charts for a great many years. Their name, however, has just been invented, and is hardly yet known to the practical forecaster.

There is a marked reluctance on the part of contemporary men of science to contribute to the scientific vocabulary. This is perhaps due to the growing ignorance of the principles of etymology to which I have already referred; though it may be also the token of a reaction from the pedantry of an older generation, which cumbered the language with terms too labored for daily use, and often with names of things that might well have been left nameless.

I have in mind a number of lexical curiosities that furnish diversion to any one who chances to read a memoir by A. Piche, "La Météorologie dans le Département des Basses-Pyrénées." From this work we learn that "meteorologistotheory" is the branch of science dealing with meteorologists; that "meteorologistopiry" has to do with experiments in the training and organizing of meteorologists; that "meteorologistonomy" relates to meteorological administration; that "meteorologistotechny" is the art of applying the laws relating to the production of meteorologists, their arrangement into groups, and the development of their labors; that "meteorologistosophy" is the philosophical study of meteorologists; etc. In short, M. Piche has stuck pins through his meteorologists as if they were so many butterflies, and has made them the subject of a new branch of natural history. His terminology is so terrifying that we are thankful the meteorologists had individual names before he got hold of them; otherwise we shudder to think what he might have done in the way of nomenclature! The same ingenious Frenchman invented an instrument for measuring the sensible temperature which he called at first the "calorisoustractometer"; but later he took pity on humanity and changed its name to "deperditometer."

Of the two evils—a clumsy term or none at all—the former is certainly to be preferred. There can be no progress in ideas without a corresponding progress in language. This fact is emphasized by Whewell; and he cites in illustration the cases of Cæsalpinus in botany, and Willughby in ichthyology, each of whom introduced excellent systems of classification which failed to take root or produce any lasting effect among naturalists because they were not accompanied by corresponding nomenclatures. No one recognized this truth more clearly than Linnæus, whose great contributions to botany were surpassed by his contributions to the language of botany. Whewell quotes a maxim from Linnæus's "Botanical Philosophy,"

Nomina si nescis perit et cognitio rerum,

which ought to be taken to heart by the many scientific men of to-day who are conspicuously shirking their obligations to the technical vocabulary.

In the history of meteorology there are innumerable instances of important ideas that led a precarious existence for years, almost ignored by meteorologists at large, because no one had crystallized them by giving them names. Think of the number of conceptions that owe their present definiteness in our minds to the felicitous terminizing of Ralph Abercromby! The seven typical forms of isobars are familiar examples. Another is the generalization "recurrence," under which term Abercromby united the many cases of the supposed tendency of particular types of unseasonable weather to occur from year to year at about the same period—Indian summer, the "Ice Saints," the "Lammas floods," the "January thaw," the "borrowing days," and a number of other similar interruptions in the regular march of the seasons—all of them more or less elusive when submitted to a rigorous analysis, but none the less deeply-rooted conceptions in the popular mind. Individually these supposed occurrences are familiar to all meteorologists, but we should probably sometimes lose sight of their generic similarity had not Abercromby given them a handy generic name.

Probably in no branch of science is the vocabulary more confused than in atmospheric optics; especially in English. This particular subject affords so many examples of the vices of the existing language of meteorology that we may profitably consider it at some length.

In a publication which, I regret to say, bears the official imprimatur of the Weather Bureau,[1] I find a definition of the "solar aureole, corona, or glory." These names are stated to belong to the familiar phenomenon of diffraction rings around the sun; and the question arises—Why three names for one thing? Etymologically one is as good as another; but the single term "corona" was long ago appropriated to the phenomenon in question. If we consult Pertner's "Meteorologische Optik," we shall find that, according to this authority at least, the aureole is not identical with the corona. A separate name was desired for that inner portion of the complete corona which is, as a rule, the only part visible; extending from the blue-white zone around the luminary to the reddish brown circle adjacent, but not including either indigo or violet. Pernter was, I believe, the first person to distinguish this part of the corona under the name "aureole." The glory, again, is something quite different. This is not seen around a heavenly body, but surrounds the shadow of the observer's head—strictly speaking, of the observer's eye—cast upon a cloud or fog-bank. In the phenomenon of the Brocken specter the glory constitutes the "Brocken bow"—though the specter and the bow are persistently confused in the dictionaries and in the literature of meteorology.

This leads us to a further hopelessly confused statement in connection with the definition above quoted, reading as follows: "A smaller circle surrounding the shadow of the observer's head is called an anthelion, aureole, glory, or fog shadow." The word "anthelion has, indeed, been used persistently in this sense in English literature; though such a use has never been countenanced in French or German. Bravais and his successors applied the name "anthelion" to what is sometimes called in English the "countersun"; viz., a white image of the sun seen at the same altitude as that luminary, but opposite it in azimuth—one of the rarer phenomena of the great halo family. Although this, the preferable, use of the name is absolutely ignored in the English dictionaries—which uniformly confuse the anthelion with the glory—it is not quite unknown to English writers. I find the "anthelion," in this sense of the term (as observed in the year 1762), described and figured in the "Philosophical Transactions" (abridged), Vol. 11, p. 532. A similar use of the term occurs in Howard's "Climate of London," 2d ed. (1833), Vol. 1, p. 222. As to "aureole," we have already seen how Pernter has desynonymized this term. "Fog shadow" is obviously a most inappropriate name for a ring of light. In short, the sentence above quoted, revised in accordance with the requirements of accurate terminology, would read: "A smaller circle surrounding the shadow of the observer's head is called a glory." The three other names are untenable.

Although I have quoted a Weather Bureau publication—because it happened to lie nearest at hand—the example selected is a fair specimen of the loose language of a majority of writers on atmospheric optics. In fact, the vocabulary is so confused that one can hardly write of any but the commonest of the photometeors without defining each term he uses; and I am not sure that even the names of the commonest are wholly unequivocal. In a recent number of Nature—a journal which is usually a purist in scientific English—the beautiful circumzenithal arc, Mascart's "upper quasi-tangent arc of the halo of 46 degrees," was referred to as a "zenith rainbow." Still more startling is it to find the new edition of Wood's "Physical Optics" ignoring the term "corona" altogether in describing the diffraction rings around the sun and moon.

In contrast to the prevailing confusion in the English vocabulary of this subject, we find that the labors of Pernter have led to the adoption of a nearly uniform terminology in recent German literature; but this writer shares with his compatriots a prejudice in favor of native terms that detracts much from the value of his contributions to the universal language of science. Thus, while he has adopted the Greek word "halo," he prefers to call a corona a "Kranz," and he clings to "Hof" as a general name for the heliocentric circles of all kinds. In fact, very few Greek or Latin names appear anywhere in his great treatise on atmospheric optics. Of course, this fact is merely typical of the almost universal preference of German science for linguistic isolation; a subject too large to enter upon here.

In French, the complicated terminology of halos was set in order by Auguste Bravais, and his labors have been admirably seconded in our own time by Louis Besson. Fortunately French science still prefers a Græco-Latin vocabulary, and the terms it introduces are easily taken over into English. No adequate account of halos has yet appeared in our language. Whoever undertakes to write one will hardly err in adopting the Bravais-Besson terminology en bloc, with only the necessary idiomatic modifications and without regard to the practise of earlier English writers on the same subject.

In the brief space remaining at my disposal I think I can not do better than to refer specifically to a few meteorological terms, of more or less recent origin, that deserve a wider use in scientific literature than they now enjoy.

Beginning at the top of the alphabet, I find that the branch of meteorology dealing with upper-air research is not yet known to all meteorologists as "aerology." This term, proposed by Köppen, and officially adopted at the Milan meeting of the International Commission for Scientific Aeronautics in 1906, is so well adapted to fill a serious gap in our vocabulary that one is surprised at the slow progress it has made in English. This is all the more surprising because, in spite of its Greek etymology, it was promptly accepted by the Germans, and is now fully established in their language. The expression "scientific aeronautics," still incorporated in the name of the international commission that has the oversight of aerological matters, is an obvious misnomer as applied to the exploration of the free atmosphere, notwithstanding the fact that aeronautical methods and appliances are largely used in this field of research.

The most remarkable occurrence in the history of aerology was the discovery, in 1902, of a region of the atmosphere originally called by its discoverer the "isothermal layer"; a name that he has since abandoned in favor of "stratosphere." A number of other names have been proposed as alternatives—in some cases for reasons that, to any one familiar with the natural history of scientific terms, seem decidedly frivolous. Thus, some of our English confrères objected to the original name because there was no certainty that the so-called "layer" had an upper boundary—an objection that has perhaps been disposed of recently by Dr. Alfred Wegener. Mr. Dines, one of the ablest of aerologists. prefers to speak only of "isothermal columns" in the atmosphere; but this plan leaves the important stratum as a whole without a name. There is every indication at present that Teisserenc de Bort's second term, "stratosphere," will ultimately prevail. It commends itself by its consonance with the term "troposphere," applied by the same investigator to the region of clouds and convective disturbances, and with Wegener's recent tentative names for supposed higher strata of the atmosphere—"hydrogensphere" and "geocoroniumsphere"; and all of these conform to the well-established terminology of "atmosphere," "hydrosphere" and "lithosphere."

Meteorology has recently profited, as to terminology and otherwise, by the writings of Henryk Arctowski, who, though a Pole by birth and a Belgian by adoption, wields a very facile pen in English. M. Arctowski is responsible for the convenient words "pleion" and "antipleion," denoting, respectively, regions of positive and negative departure from a normal. Thus, a temperature pleion. or "thermopleion,"[2] lay over western Europe during most of the summer and early autumn of 1911. Lines of equal positive and negative departure from normal temperature (not "anomalies," which are departures of local means from the means of latitude circles) were unnamed until Arctowski called them, respectively, "hypertherms" and "hypotherms." All these terms are correctly formed from Greek roots, are easily assimilable into our language, and are well fitted to give definiteness to a group of ideas that formerly suffered in this respect by the lack of a terminology. Nevertheless, their use has not spread since they were proposed, two or three years ago. It is to be hoped that they are not destined to share the oblivion of some analogous terms relating to atmospheric pressure proposed about forty years ago by Prestel; viz., "pleiobar," "mesobar" and "meiobar."

Purely English terminology has received some useful amendments at the hands of Dr. Hugh Robert Mill, who in this respect is carrying on the worthv traditions of "British Rainfall." Thus he has balanced Symons's terminology of droughts—the "absolute" and the "partial" drought—by introducing the term "rain spell" for a period of more than 14 successive days with rain. This expression, however, like the term "rain day," is one that would need to be redefined in other countries. Dr. Mill has rendered an even more useful service to precise terminology by distinguishing between the words "mean," "average" and "general." He speaks, for example, of the mean temperature at Camden Square during the month of June, 1900; the average temperature at the same place in June during a ten-year period; the general rainfall over the whole county of London in May, 1910, and the average general rainfall over the same region for a term of years.

British meteorologists have also succeeded in establishing a working terminology in English for the various deposits of frozen moisture that have occasioned so much fruitless discussion at international meteorological meetings. The Meteorological Office now applies the term "rime" to the rough deposits due to fog, and "glazed frost" to the transparent smooth coating usually caused by rain which freezes as it reaches terrestrial objects. The ambiguous expression "silver thaw" has been discarded in British meteorology.

The endless subject of cloud terminology and nomenclature can not be discussed in this paper; but I wish to call attention to one term in this connection recently introduced by M. Besson. This is the name "nephometer" for an instrument used in measuring the amount of cloudiness, as distinguished from the familiar "nephoscope," by which we observe the positions and movements of individual clouds.

German meteorologists have lately introduced the all-Greek names "chionometer" and "chionograph," and the hybrid "nivometer," for the instruments used in measuring snow. Although these terms will hardly displace "snow-gage" in English, we shall probably find it convenient to use their derivatives; e. g., "nivometric"; just as we use "pluviometric," though we generally avoid "pluviometer."

The name "ceraunograph" applied by Odenbach in 1891 to his variety of the thunderstorm-recorder now seems destined to become the generic and international designation for the numerous instruments of this class. Particular forms have been known as "thunderstorm-recorders," "lightning-recorders," "brontometers," "brontographs," "ceraunometers," "electroradiographs," etc. "Ceraunophone" will. accordingly, be the natural designation of the modification of the ceraunograph in which a telephone-receiver takes the place of a recording pen.

Our Weather Bureau has recently contributed to the meteorological vocabulary the name "kiosk," applied to a little pavilion in which working meteorological instruments are displayed for the benefit of the public. Although the connotations of this word are hardly consistent with the style of architecture adopted for these structures in America, no better designation has been proposed, and it is safe to assume that "kiosk," as well as the object so named, has come to stay. It is rather curious that, although "Wettersäulen" have been familiar objects in Germany for half a century, their use has only recently spread to English-speaking countries, and the need of an English name for them has only recently made itself felt.

When the first complete English meteorological dictionary makes its appearance it will need to take account of fully ten thousand words and phrases; and in connection with hundreds of these much work must be done in tracing their vicissitudes and in bringing them into something like conformity with a systematic and workable language. The terms I have mentioned in the foregoing paragraphs are, in the language of the day, "a drop in the bucket."

In closing, I wish to repeat a recommendation that I recently made to the International Meteorological Committee, through the kind intermediation of the chief of the Weather Bureau, in behalf of the creation of an international commission on terminology, analogous to the commissions already established by the committee on various other meteorological subjects. The utility of such a step is well attested in the history of other sciences. In electricity, for example, the useful names of the electrical units—"ohm," "volt," "ampere," "coulomb," "farad," "joule," "watt" and "henry"—were all promulgated by formal international agreement.

The International Meteorological Committee and Conferences have, it is true, given us official definitions of a few terms; but such work can not be done on an extensive scale save by a body especially created for the purpose and having far more time at its disposal than is available at the ordinary triennial assemblies of meteorologists.

Pending the consummation of this wish, let me urge meteorologists to familiarize themselves with the neglected language of their science; to avoid coining needless synonyms of terms that already exist; and, when a new term is really needed, to create one with due regard to the analogies of the language and its availability for international use. Generally speaking, only Greek and Latin derivatives answer the latter requirement. If a meteorologist feels himself unequal to framing a valid word from the classical vocabularies, he can always appeal for aid to some friendly colleague of philological attainments.

  1. Monthly Weather Review, Vol. 33, p. 527. This is, however, substantially a quotation from the Smithsonian Meteorological Tables.
  2. M. Arctowski's terminology is not quite consistent, since he does not speak of "thermoantipleions," but of "thermomeions." As "antipleion" is an awkward form in combinations, it is unfortunate that it was adopted as the generic term. "Meion" is preferable.