THE SOLAR HYPOTHESIS. 243 



of minimum sun-spots and those of maximum sun-spots, would cause pronounced changes 

 in the Rhone glacier, provided the low temperature lasted long enough to allow of the 

 abundant accumulation of snow. In that case, if the form of its valley were favorable, 

 the Rhone glacier might become 5 miles longer than it now is; or, if the gradient of the 

 valley bottom be assumed as uniform, the ice might descend 90 feet below its present level; 

 or the glacier might increase 28 feet in thickness. The exact nature of the change in the 

 glacier and its exact dimensions would depend upon the topography of the Rhone Valley 

 and upon the relation of precipitation to temperature, winds, and other meteorological 

 phenomena, but the figures which have just been given show the order of magnitude of the 

 results which might be expected from a lowering of the mean annual temperature of the 

 earth to the extent of 0.26° C, provided always that the change were permanent rather 

 than temporary. A change of temperature capable of producing such results, or even 

 results half as great, would scarcely seem to be too small to produce "any important effect 

 upon meteorological phenomena." The truth of Newcomb's conclusions appears to be at 

 least an open question. 



Let us turn now to the other great objection to the theory of an eleven-year climatic 

 cycle due to the sun: Regions within the tropics may show fairly strong indications of 

 such a cycle, but even there a certain number of apparent contradictions are found, while 

 as higher latitudes are gained the indications appear to become much less distinct and 

 more contradictory. Is such a state of affairs consistent with the theory of the cUmatic 

 influence of sun-spots? At fu-st sight one is incUned to answer with a categorical negative, 

 but the recent meteorological investigations of Arctowski oblige us to reconsider the 

 matter. By a patient sifting of a vast mass of figures he has shown that both in Europe and 

 America there appear to be areas of abnormal pressure, temperature, rainfall, and the like, 

 which persist for several years and move irregularly backward and forward.* His con- 

 clusions are based partly on direct meteorological records and partly upon statistics of the 

 growth of wheat or corn. His method can best be described by means of specific examples. 

 Taking as a standard the mean temperature of the various portions of the United States or 

 Europe, Ai-ctowski has computed the departure of each station from the normal. At first 

 he did this by years, but in his later work, which is not yet pubUshed, by months. The 

 results are striking. He finds that the regions where the mean temperature for the given 

 period is above or below the normal are not distributed irregularly but with much system. 

 He does not find one region showing excess while its immediate neighbor shows deficiency, 

 and the one beyond that again excess. On the contrary, the excess of temperature is 

 greatest at one particular point ; from there it decreases gradually until the area of normal 

 temperature is reached, beyond which the excess gives place to deficiency, which in turn 

 centers around a definite spot. The degree of regularity is such that lines of equal excess 

 or deficiency can be drawn in the same fashion as isotherms. These present almost the 

 appearance of the isobars of a barometric map, as is illustrated in figures 77 to 80. These 

 particular maps represent the corn crop, but maps of temperature, pressure, or the growth 

 of other crops would have the same general appearance, although the areas of excess or 

 deficiency would be different in each case. The areas which are above the normal in 

 temperature have been termed "pleions" by Arctowski, and those below normal "anti- 

 pleions," those above or below the normal in pressure are called areas of "hyper-pressure" 

 and of "hypo-pressure," while places having an excess or deficiency of crops are desig- 

 nated " fats " and "leans." For the sake of convenience, however, I shall depart somewhat 

 from his usage, and shall speak of all areas of excess as pleions and all areas of deficiency 

 as anti-pleions. Thus we may have a pleion of temperature, crops, or pressure, and the 

 three may be quite urn-elated to one another. In the year 1901 it will be seen that so 



♦Bulletin American Geographical Society, vol. 42, 1910, pp. 270 and 481; vol. 44, 1912, pp. 598 and 745; vol. 

 45, 1913, pp. 117-131. L'enehalnement des variations climatiques, Bruxelles, 1909. 



