C. L. Jordan on Coriolis and the Florida State University deflective force Tallahassee, Fla. Coriolis force or deflective force of the Encyclopedia Britannica published in 1922 does Now every meteorology student soon encounters the not carry an item on Coriolis or coriolis force. Begin- name Coriolis in association with the apparent deflective ning around 1930, practically every physics text which force due to the earth's rotation. This association is, how- discusses the influence of the earth's rotation on moving ever, a relatively recent innovation since Coriolis was objects refers to the coriolis force or acceleration. given little recognition by meteorologists for about 100 years following the publication of his 1835 paper deal- Recognition given Coriolis in the 1880-1930 period ing with accelerations in relative coordinate systems The lack of recognition of Coriolis by meteorologists (Coriolis, 1835). In the United States and Great Britain, may have been due to a complete ignorance of his work the terms deflective force and deviating force (of the within some groups and, among others, to a lack of ap- earth's rotation) were in general use until about 1940. preciation of the general applicability of the ideas pre- Widely used texts in the 1930's, such as Brunt (1934) and sented in his 1835 paper. Several references to Coriolis Humphreys (1928), make no reference to Coriolis or to have been noted during the 1880-1930 period (cf. the coriolis force and these items do not appear in the Sprung, 1881; Gunter, 1899; Ekman, 1905; Shaw, 1926) third edition of the Meteorological Glossary (Meteoro- but none of these refer to the deflective force as the logical Office, 1940). There are, however, references to coriolis force. In some cases exclusive credit was not the coriolis force, the coriolis parameter and the coriolis given to Coriolis for describing the deflective force. For factor in research papers published in the United States example, Gunter mentions Coriolis and Ferrel, while Ek- and Great Britain during the 1930's (cf. Rossby, 1936; man mentions Hadley, Coriolis and Ferrel. Shaw (1926) Montgomery, 1937; Sutcliffe, 1938). referred to Coriolis in his bibliography of theoretical The association of Coriolis with the deflective force meteorology, but not in the body of his four-volume probably occurred somewhat earlier in Europe than in treatise, and he incorrectly stated that the 1835 paper the United States or Britain. V. Bjerknes et al. (1933) dealt with "the relation of wind to pressure." and Koschmieder (1933) refer to the coriolis force and There were also papers written in this early period Dr. Erwin R. Biel has informed the writer that this term of dynamic meteorology which should have carried ref- was used in lectures at the University of Vienna in 1924. erences to Coriolis but failed to do so. In a nineteenth- However, many of the well-known texts appearing in century paper dealing with the deflective force, Davis western Europe in the first third of this century, includ- (1885) attributes "the first correct and complete discus- ing Angot (1907), Defant (1926) and Suring (1927) carry sion of the (deflective) force" to Poisson. The same view no reference to Coriolis or the coriolis force. It is inter- was expressed by Abbe (1910) who, in die introduction esting that during the period 1880-1930 practically every of his third volume of translations, stated that: . it text carried a reference to Buys Ballot but not to Cori- was Poisson who, in 1837, first deduced correctly the olis, while in the recent years the trend is reversed with influence of the earth's rotation on moving solids, and many texts having no reference to Buys Ballot's law. Tracy who in 1843, applied similar views to the rotation of storms." It is indeed surprising that Abbe, who did so Recognition given Coriolis by the physicists much to introduce dynamic meteorology in the United A rather cursory examination of texts in general physics States through his translations made over a period of and mechanics published in the early part of this century more than 30 years, was apparently unaware of the 1835 revealed that most, but not all, authors referred to paper by Coriolis. The paper by Sprung (1881) men- Coriolis in discussing the deflective force but the terms tioned previously which carried a reference to Coriolis coriolis force and coriolis acceleration had not come into was included in Abbe's translations but the date of the use. For example, Routh (1905) and MacMillan (1927) Coriolis paper was erroneously given by Sprung as 1861. refer to Coriolis but speak of the deflective force as the It is interesting to speculate that had it not been for compound centrifugal force. On the other hand, Jeans this error by Sprung, Abbe probably would have in- (1907) makes no reference to Coriolis in discussing the cluded a translation of Coriolis' 1835 paper rather than deflective force. It is of interest that the eleventh edition a portion of one by Poisson. There are other interesting Bulletin American Meteorological Society 401 Unauthenticated | Downloaded 10/07/21 08:50 AM UTC Vol. 47, No. 5, May 1966 portions of Abbe's introduction previously cited which and, according to Dugas (1955), some felt that Coriolis' suggest that his evaluation of the important early con- work added little, if anything, to Clairaut's principles. tributors to dynamic meteorology was somewhat different Following Coriolis' paper in 1835, which considered rela- than might be gained by reference to current texts. For tive accelerations in a very general manner, Poisson 1 example, he wrote . the modern study of this sub- (1838) considered the question of the deflection of pro- ject (dynamic meteorology) is properely traceable to the jectiles fired from the earth. The treatment of the deflec- influence of Prof. William Ferrel in America and Prof. tion of air currents, first discussed by Hadley, was William Thomson in England, both of whom cooperated extended by Tracy (1843) who showed by qualitative to put our knowledge of the subject on a firmer basis reasoning that any air current, irrespective of initial than was before possible. Meanwhile, a profound Rus- direction, would be deflected to the right in the North- sian, Braschmann, and the equally profound German ern Hemisphere. The first complete treatment of the scholar, Erman, were independently working over the deflective force from the meteorological point of view is same ground, though their publications have been that of Ferrel who, in the late 1850's, considered the scarcely noticed by technical meteorologists." There is relative accelerations in mathematical terms and derived little doubt that Ferrel, the father of dynamic meteorol- appropriate expressions for inclusion in the equations ogy in the United States, has not received the credit he of motion as applied to the atmosphere. deserves and, as discussed by McDonald (1963) in an It is not the purpose of the note to propose that the article rich in meteorological history, the contributions coriolis force be renamed. It is of interest, however, to of Thomson (Lord Kelvin) to meteorology have been raise the question why Coriolis' name has been given to almost entirely overlooked by meteorological authors in the deflective force in view of the important contribu- this century. tions of some of the individuals cited above. It might Ferrel's contributions seem that, somewhere along the way, some convincing The first complete treatment of the deflective force as articles might have been required to lead the meteoro- applied to atmospheric flow patterns is almost certainly logical community to give priority to Coriolis over Had- due to Ferrel, although the basic concept of accelerations ley, Tracy and Ferrel. In view of the literature pre- in rotating coordinate systems goes back to Coriolis. This viously cited, it would seem that such articles, if they view was expressed by Humphreys (1942) who, in sum- exist, would probably have been written some 80-100 marizing Ferrel's contributions to meteorology, wrote: years following Coriolis' death. A search of the standard "And yet while all the ideas developed in his mathemati- meteorological journals appearing in English, as well as cal papers were original with Ferrel, they nevertheless of Science and Nature, for the period 1925-1940 failed had been anticipated in a general way in 1835 by Cori- to turn up any articles of this type. It may have been olis." Ferrel's work on the deflective force first appeared that little thought was given to priorities and the term in a series of papers in Runkle's Mathematical Journal coriolis force was readily adopted since it represented a in the late 1850's and was summarized in an article in replacement for the rather awkward term deflective force the American Journal of Science and Arts (Ferrel, 1861). of the earth's rotation. There may be much better rea- Actually the approach in the 1861 paper is more mod- sons for the adoption of the term coriolis force by the ern and complete than given in later papers (cf. Ferrel, meteorologists and it is hoped that these will be forth- 1872) in which attempts were made to introduce em- coming from the readers of this article. pirical quantities into the equations to make them more useful for the synoptic meteorologist. Acknowledgments. The writer is indebted to Profes- The matter of credit sors Erwin R. Biel and James E. McDonald for helpful The question of credit for the discovery of a scientific suggestions and to Mr. Silvio F. Lombardi for his assist- principle is usually difficult to establish. This is true in ance in the literature search which was made during the the case of the deflective force of the earth's rotation preparation of this paper.