Page:Popular Science Monthly Volume 82.djvu/281

Rh 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," 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.