March 17, 1922] 



SCIENCE 



293 



are described. But a significant exception to 

 this rule is to be found in Professor Robert 

 ;DeC. iWard's recent discussion of the new 

 temperature charts of the United States.^ In 

 this paper, Professor Ward has woven about 

 certain fine charts, which are to appear eventu- 

 ally in the section on "Climate" in the Atlas 

 of American Agriculture (U. S. Department 

 of Agi-iculture), a moving story of isotherms 

 so fascinating that one reads to the very end 

 without the least fatigue; — this is noteworthy 

 because it is exceedingly difficult for most 

 authors to avoid the prosaic when dealing with 

 such a subject. But the dynamic qualities of 

 the paper are not more impressive than the 

 skill displayed in drawing from the isothermal 

 complex, the broad and significant climatic 

 features of these extraordinary charts. 



From a large number of charts furnished the 

 author through the courtesy of Dr. 0. E. Baker, 

 Professor C. F. Marvin, and Mr. J. B. Kincer, 

 twenty have been selected for discussion and 

 are reproduced as lithographs in the Monthly 

 Weather Review. The charts include monthly 

 means for each of the twelve months, average 

 winter temperatures, mean annual ranges, low- 

 est mean monthly temperatures recorded in 

 January and July, absolute maxima and mini- 

 ma, and average annual minima. These repre- 

 sent a distinct advance over earlier charts in 

 that topography has been carefully considered. 

 The mountainous west, therefore, on most of 

 the charts, presents a very complex appearance, 

 for there the influence of altitude is most clear- 

 ly shown. The river valleys, such as those of 

 the Rio Grande and the Colorado, could be 

 readily detected by the trend of the isothenns 

 were the base map lacking; the Appalachian 

 region introduces warping and many local ir- 

 regularities. The crowding of the isotherms 

 in the Rocky Mountains, however, prevents 

 such broad generalizations as are possible in 

 the East. 



1 Some characteristics of United States tem- 

 peratures. Monthly Weather Review, November, 

 1921, pp. 595-606. A limited number of reprints 

 of this article will be available shortly, and may 

 be obtained upon application to the Chief of the 

 Weather Bureau, Washington, D. C. 



Beginning with a broad, world-view of the 

 trend of isotherms across the continents, the 

 author shows how the great ocean cuiTents 

 crowd the isotherms in latitude on the east 

 coasts and spread them apart on the west 

 coasts. This accounts for the mild climate of 

 the west coast of Europe as compared with the 

 east coast of the United States. In middle 

 and lower latitudes, the east and west coasts 

 of the United States do not differ materially 

 in mean annual temperature, but in northerly 

 latitudes, the mildness of the Pacific Coast 

 asserts itself. In latitude 45° N., for instance, 

 the mean annual temperatures are about 10° 

 F. higher on the west than on the east coast; 

 while San Diego, Calif, and Charleston, S. C, 

 in the same latitude, have approximatehr the 

 same mean annual temperature. 



A striking feature of the mid-winter chart 

 is a southward curving of the isotherms over 

 the northern interior districts, "which empha- 

 sizes, among other things, the fact that the 

 western border of the Great Plains and the 

 eastern foothills of the Rocky Mountains are 

 warmer in spite of their greater elevation than 

 the lower-lying country farther east." Pre- 

 vailing off-shore winds along the Atlantic and 

 Gulf coasts prevent the full eft'eet of the mod- 

 erating infiuence of these warm waters to be 

 realized. But, in spite of this, the isotherms 

 bend in general accord with the coast lines. 

 The moderating effects of water are also ob- 

 served to leeward of the Great Lakes. Along 

 the Pacific coast, on-shore winds cause the 

 isotherms to parallel the coast, thus affording 

 an interesting comparison of the effect of pre- 

 vailing winds and latitude controls, the Atlan- 

 tic coast being conspicuously subject to the 

 latter. 



The January mean temperature is much 

 higher on the west coast than on the east, in- 

 creasing, as was the case with the mean annual 

 temperature, in effectiveness with increase of 

 latitude. The coast of Oregon is 20° F. warm- 

 'ei- ithan ithe corresponding latitude on tihe 

 Maine coast. The direction of the pilgrim- 

 ages of seekers for balmy climates, the shift- 

 ing of transportation from the Great Lakes to 

 railroads upon the close of navigation, the 



