86 



SMITJISONIAX MISCRLLANEOrS COLLFXTKIXS 



\'0L. 6 



111 Dctoljer. Dr. .Michelson left for Kansas to investigate the Sauk 

 and ]-"ox of the Missouri and adjacent triljes. A prehminary survey 

 was all that was attempted owing to the inclemency of the weather. 

 Some myths, ohtained among the Foxes of Iowa, were also translated, 

 and the investigator returned to \\'ashington for office work. 



Fk;. 85.-- a Catawba hoartli with puttfry. Plic)toi.;Tapli hy Michelson. 



EXPEDFIJON OF THE ASTROPFl VSICAL OBSERVATORY 



Mr. T.. 1^.. Aldrich proceeded to Mount Wilson in July, 1913, for 

 the purpose of measuring the solar radiation. He was joined there 

 at the end of August l)y Director Abbot. Several kinds of work were 

 undertaken ; hrst, the usual spectro-bolometric determination of the 

 solar constant of radiation. This work has now been carried on dur- 

 ing every summer at Mount Wilson from 1905 to 1913 inclusive, ex- 

 cepting the year 1907. It has resulted in showing an irregular vari- 

 ability of the sun from day to day, and a dependence of the sun's 

 radiation on the number of sun-spots. It has also yielded a value of 

 the solar constant of radiation believed to l)e correct within one ])er 

 cent. Since there have been criticisms of the value, however, on the 

 ground that it is imj^ossible to correctly estimate the losses of radia- 

 tion in the earth's atmosphere, it was felt desirable to check the result 

 by sending up self-registering a])]:)aratus attached to free balloons 

 to the highest possible altitudes. 



This work was undertaken by Mr. Aldrich in July in cooj^eration 

 with the I'nited States Weather Bureau. Balloons were sent up on 

 five days from Santa Catalina Island, carrying in each instance a self- 

 registering p}rheliometer devised and tested at the Smithsonian 

 Astro])hysical ( )l)servatory, and a self-registering apparatus of the 

 W'eather llureau, which records the tem])erature, ])ressure, and 

 humidity of the atmosphere. 



