628 



SCIENCE 



[N. S. Vol. XXXVIII. No. 985 



Atmospliarisclie Electricitat," ^ lias pointed 

 out that although weather affects atmospheric 

 electricity the effects of the latter on the 

 former are unknown. Mr. Carl Stormer's ex- 

 pedition to Bossekop, February 28 to April 1, 

 1913, secured 636 pairs of simultaneous photo- 

 graphs of the aurora from points 27 kilometers 

 apart, most of which are very satisfactory for 

 computing with a large degree of accuracy the 

 form, position and altitude of all the prin- 

 cipal kinds of aurora. Prismatic and kine- 

 matic photographs were also taken. The full 

 results will be published in considerable detail 

 later.^ 



SOUTHERN HEMISPHERE SEASONAL CORRELATIONS 



A CONTINUED article on this subject by Mr. 

 R. C. Mossman, of the Argentine Meteorolog- 

 ical Office, is now appearing in Symons's 

 Meteorological Magazine* Abnormal condi- 

 tions in one " center of action " " are accom- 

 panied by abnormal weather in others, and 

 often indicate future conditions at distant 

 points — a fact now used successfully in sea- 

 sonal forecasts in India. A pronounced fea- 

 ture of many correlations is their temporary 

 character, this applying more particularly to 

 pairs of stations not located in action centers. 

 For instance, from 1876 to 1894 an excess of 

 rainfall at Trinidad from April to September 

 was generally followed by a deficiency in rain- 

 fall during the next six months at Azo, Argen- 

 tine Republic. Little correlation is shown 

 before or after the above period. Java rain- 

 fall from October to March, 1880 to 1909, was 

 generally the reverse of Trinidad rainfall for 

 the following six months. Thus an excess of 

 rainfall at Java for the months October to 



2 Das Wetter, Berlin, 1913, pp. 49-56, 128-133, 

 173-178. . 



'From Nature, London, 1913, Vol. 91, pp. 584- 

 585 (with reproductions of some of the photo- 

 graphs). Also Meteorologisehe Zeitsehrift, 1913, 

 pp. 410-412. 



*Vol. 48, pp. 2-6, 44-47, 82-85, 104-106, 119- 

 124. 



° By ' ' center of action ' ' is meant one of the 

 more or less permanent cyclones or anticyclones in 

 control of the atmospheric circulation over a large 

 area — e, g., the Iceland cyclone, the Azores anti- 

 cyclone. 



March gave indication of an excess to follow 

 at Azo one year later. 



CHANGES OF CLIMATE IN THE SOUTHWEST 



Such changes during historical time as in- 

 dicated by tree rings and " climatic terraces "' 

 have recently received the attention of Messrs. 

 A. E. Douglass" and Ellsworth Huntington.' 

 Mr. Douglass found by a test extending over 

 forty-three years that the radial thickness of 

 the rings of the yellow pine of northern Ari- 

 zona gives a measure of the rainfall in that 

 region with an average accuracy of over 70* 

 per cent. Through examination of the rings- 

 of 100 trees, of which five were measured to- 

 the number of 400 rings and two to 500, a 

 2a-year and a 11.4-year variation, eaclii 

 amounting to 16 per cent, of the mean were- 

 found. Its plot derived from 492 years shows- 

 two maxima which correspond in time with 

 two maxima of rainfall in the 50 years of 

 records on the south California coast. These' 

 in turn match with the major and minor 

 maxima in the temperature of that region for 

 the same period. The larger maximum of 

 the latter occurs at the time of the sun-spot 

 minimum as averaged for 125 years. Mr.. 

 Huntington supports these and his own results- 

 from studies of tree rings with evidences from 

 alluvial terraces (5 to 1,000 feet high) of the- 

 rather dry mountainous regions of the south- 

 west. These terraces are ascribed to varia- 

 tions in stream erosion or lake level due to- 

 variations in rainfall. Mr. Huntington hag- 

 discussed this subject fully in previous works 

 (" Explorations in Turkestan " and " The- 

 Pulse of Asia ") and intends soon to discuss 

 it with regard to America. 



" ' ' Pine Trees as Recorders of Variations in 

 Rainfall, ' ' Astron. and Astrophys. Soc. of Amer- 

 ica. Abstract in Bull. Int. Inst, of Agric. and in 

 Quarterly Journal of the Eoyal Meteorological' 

 Society, 1913, pp. 244-245. 



' ' ' The Shifting of the Climatic Zones as Illus- 

 trated in Mexico," Bull. Am. Geogr. Soc., 1913^ 

 pp. 1-12; Geogr. Journ., June, 1913; Quarterly 

 Journ. of the Boy. Met. Soc, 1913, pp. 245-246, 

 ' ' Secret of the Big Trees, Yosemite, Sequoia and' 

 General Grant National Parks," Pub. U. S. Dept> 

 of the Interior, 1913, 24 pp., 14 figs. 



