THE SOLAR HYPOTHESIS. 241 



seems fair to suppose that the maximum price would, on an average, be reached within a 

 year after the minimum crop was harvested. The worst crops in England are those of the 

 wettest years when the ground is waterlogged and there is scanty sunshine. Hence we 

 may infer that in the period from 1610 to 1754 a. d. the maximum rainfall in England 

 occurred on an average one or two years before the time of maximum sun-spots. In studying 

 the sequoias of California we found that the maximum growth comes on an average about 

 two years after the maximum rainfall. In the curves before us the maximum of the 

 unsmoothed curve for the first period comes two years after the sun-spot maximum, and 

 that of the smoothed curve one year. In the later period the same relation is observed. 

 Subtracting two years from the time of maximum growth, we find that the probable time 

 of maximum rainfall in California is a year or less before the sun-spot maximum, a result 

 which agrees closely with that obtained in England and suggests that these two regions in 

 the western parts of two great continents fare somewhat similarly, so far at least as winter 

 rains are concerned. This agrees with the conclusion derived from our curves of changes 

 of chmate in America and Asia for the past 2,000 or 3,000 years. When minor fluctuations 

 are eUminated, times of heavy precipitation in the corresponding parts of the eastern 

 hemisphere and of America seem approximately to coincide. 



The chief objections to the theory of an 11-year cHmatic cycle due to sun-spots are 

 two. In the first place, while it must apparently be granted that the earth's temperature 

 actually varies in harmony with the spots of the sun, the variation is so slight that many 

 of the highest authorities consider it too small to have an appreciable effect. In the 

 second place, while the various meteorological elements, especially rainfall and tropical 

 cyclones, show some indications of a cycle corresponding with that of the sun, the evidence 

 of this is thus far largely confined to the region within the tropics. Even there, and still 

 more in other places, curious contradictions are noticed. Let us examine each of these 

 objections in detail. 



Our consideration of the objection that changes in the amount of heat received from 

 the sun are insufficient to cause appreciable meteorological phenomena may well center 

 on an article by Newcomb.* This article is so important that its appearance, together 

 with that of a similar article by Bigelow, led Hann to add an appendix to the first volume 

 of his "KUmatologie" after the main volume was finished. 



Newcomb's study of the relation of the temperature of the sun to that of the earth is 

 the most comprehensive and accurate that has yet been made. His conclusions are so 

 careful and conservative that they can scarcely be doubted so far as they are based du'ectly 

 upon statistics. He expresses himself thus (p. 379) : 



"A study of the annual departures [from mean temperature] over many regions of the globe 

 in equatorial and middle latitudes shows consistently a fluctuation corresponding with that of 

 the solar spots. The maximum fluctuation in the general average is 0.13° C. on each side of the 

 mean for the tropical regions. [The maximum temperature coming at times of minimum sun- 

 spots.] The entire amplitude of the change is therefore 0.26° C. [0.47° F.], or somewhat less 

 than half a degree of the Fahrenheit scale." 



On an earlier page (341) he says: 



"Although the reality of this 11-year fluctuation [both solar and terrestrial] seems to be 

 placed beyond serious doubt, the amplitude being several times its probable error, its amount is 

 too small to produce any important direct effect upon meteorological phenomena." 



Again, on page 384, he puts in italics the last part of the following quotation: 



"It follows as the final result of the present investigation that all the ordinary phenomena 

 of temperature, rainfall, and wi7ids are due to purely terrestrial causes, and that no changes occur in 

 the sun's radiation which have any influence upon them." 



* A Search for Fluctuations in the Sun's Thermal Radiation through their Influence on Terrestrial Temperature, 

 by Simon Newcomb. Trans. Am. Phil. Soc. U. S., vol. 21, v, 1908. 



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