CYCLES 115 



TERRESTRIAL REACTION 



Radiation and terrestrial temperatures — H. H. Clayton (1917 to 

 1926), while in the Argentine Republic, began using daily reports of 

 the solar constant wired from Calama, Chile, in prediction of weather 

 conditions for the succeeding 10 days over northern Argentina. This 

 work he is continuing over parts of the United States in collaboration 

 with C. G. Abbot, of the Smithsonian Astrophysical Observatory, 

 under whose direction the solar-constant measures are made. Such 

 prediction is based on direct effects in temperature observed in the two 

 weeks or so following changes in the solar constant. Though still not 

 accepted as conclusive by some (Marvin, 1925, etc.), the abundant 

 tests already made seem to the writer to indicate a positive link in the 

 chain of solar influence and terrestrial reaction. The full set of reactions 

 as they spread over the earth is doubtless incredibly complex, and 

 this appears to indicate something of the way the larger effects begin. 



Radiation and drought — Dr. F. E. Clements (1921), who is work- 

 ing on the relation of drought to sunspot numbers, found from the 

 rainfall records that when the relative numbers exceeded 80, a drought 

 period of two or more years followed in the western United States. 



Electrostatic reactions — The electrostatic charge in the atmosphere, 

 earth-currents, and other electric conditions show response to solar 

 activity. Dr. L. A. Bauer, of the Department of Terrestrial Mag- 

 netism of the Carnegie Institution, has done extensive correlation work 

 (1923) and considers that terrestrial magnetic conditions vary with 

 " agitated" solar conditions perhaps, rather than merely with extreme 

 solar departures from the normal. Dr. Fernando Sanford, at Palo Alto, 

 California, is making extensive records of atmospheric electricity and 

 earth-currents and finds solar influence in a marked degree. 



Glacial varves — Baron Gerard de Geer, of Sweden (1910, etc., 

 1926, 1927), has invented a method of measuring time by the annual 

 clay layers, or varves, deposited under water during the retreat of the 

 glaciers on the Scandinavian Peninsula and elsewhere. The process is 

 given a firm scientific basis by a system of cross-identification of 

 layers in different localities, similar to the cross-identification of tree- 

 rings used in the present work. By this means he is able to enumerate 

 several series of years, totaling some 18,000 since the glacial period. 

 Measurements are made of the thickness of the layers, and thus evi- 

 dence is found of temperature variations over long periods. The 

 absolute date of these clay layers is known only within several hundred 

 years. Dr. E. Antevs has applied the process in the valleys of the 

 Connecticut and Hudson Rivers and at other points, finding some 4,000 

 years in the retreat of the glacial ice up the Connecticut Valley. 

 These long sequences of annual layers displaying a temperature effect 

 will be of greatest value in studying past climates. 



