proceedings: Washington academy 237 



There are at least three basic questions which must be answered in 

 the affirmative before we can accept Mr. Clayton's views; these are: 

 (i) Are they in accord with the theoretical, physical or scientific prin- 

 ciples which we believe govern the phenomena? (2) Are the data em- 

 ployed so entirely free from systematic errors as to be practically un- 

 impeachable for the purposes for which Mr. Clayton has used them? 

 (3) Are the methods of analysis and treatment of the data sufficiently 

 conclusive to command confidence and carry conviction? 



From my understanding of the whole question at the present time» 

 I am obliged to entertain a negative reply to each one of these ques- 

 tions to such an extent as to make me believe Mr. Clayton's proposi- 

 tion is not yet conclusively proven, (i) In 1916, I was called upon 

 to decide concerning the merits of another case of correlation between 

 terrestrial weather and certain well-known solar features; in this case 

 the spottedness of the sun. At that time I formulated a physical 

 principle which seems to me to serve as a guide in questions of this 

 kind. This was published in the Monthly Weather Review for Janu- 

 ary, 1 919, and is as follows: 



"Meteorologists have long been accustomed to ascribe practically 

 all atmospheric motions, both local and general, to the gravitational 

 flow resulting from the local and general contrasts of temperature over 

 the surface of the earth. The atmosphere derives its heat, not directly 

 from the sun, except to a small extent, but chiefly from the surface of 

 the earth itself. The daily sequence of sunshine and darkness; the 

 varied distribution of clear and cloudy skies; diversities of surface cover 

 added to contrasts of land and water areas, including the phenomena 

 of evaporation, condensation and precipitation; the cycle of the sea- 

 sons, and above all the fluctuating but nevertheless perpetual contrasts 

 of surface temperatures, ranging all the way from the heat of the 

 tropics to the intense cold of the polar zones constitute a complex 

 series of varied and changeable influences seemingly abundantly ade- 

 quate to cause and explain every feature of our weather conditions, 

 however changeable we may find them. 



"These differences and contrasts on the one hand perpetually disturb 

 the orderly arrangement of air densities and pressures demanded by 

 gravity. The latter, on the other hand, as perpetually and continu- 

 ously sets portions of the air in motion, in order to establish and main- 

 tain a state of equilibrium, which, however, is never attained, or rather 

 we must clearly recognize that the ceaseless complex changes in and 

 motions of, our atmosphere represent in fact the only state of equilibrium 

 possible between gravity on the one hand and solar heating of the earth 

 on the other. 



"Seemingly with little regard for the considerations just mentioned, 

 many have sought and still seek to ascribe terrestrial weather — that 

 is to say, all the characteristic features of atmospheric variations— to 

 minor features of solar activity, as, for example, to the spots and faculae 

 of the sun or to its magnetic manifestations, or to the relatively small 



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