34 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1908. 



different parts of the sun's disk, and preliminary measurements, re^ 

 quiring exceptional care, of the absorption of water vapor in long 

 columns of air, for the region of the spectrum Avhere rays are chiefly 

 emitted by the earth. 



The Smithsonian expedition to Flint Island in the southern Pa- 

 cific to study the solar eclipse of January 3, 1908, was made in co- 

 operation with Director Campbell, of the Lick Observatory, the party 

 being absent from Washington from November 5, 1907, to February 

 12, 1908. It was proposed to measure, with that extremely sensitive 

 electrical thermometer called the bolometer, the intensity of the 

 radiation of the solar corona, and to determine the quality of coronal 

 light as compared with sunlight. This is an observation that it is 

 very unlikely will ever be possible except during an eclipse. In 

 general terms the bolometric results indicate that the coronal radia- 

 tion differs but little in quality from that of the sun, and is in fact 

 far richer than the reflected rays of the moon in visible light, 

 although less rich than skylight. Observations as to the nature of 

 the corona were such as to lead at least to the suggestion that gases 

 are present along with solid and liquid particles. The exact con- 

 clusions reached are given fully in the report of the director. 



The second volume of the Annals, issued in April, includes an 

 account of the work of the Observatory from 1900 to 1907. Com- 

 mendatory notices by letter and in the journals and requests for 

 copies of the work have been numerous. Speaking broadly, the 

 energy of the Observatory was devoted, during the period covered 

 by the volume, to an investigation of the intensity of the rays of the 

 sun and the dependence of the earth's temperature upon the radia- 

 tion. The investigations have resulted in apparently definitely fixing 

 the approximate average value of the " solar constant " at 2.1 calories 

 per square centimeter per minute, and in showing decisively that 

 there is a marked fluctuation about this mean value sufficient in 

 magnitude to influence very perceptibly the climate, at least of the 

 inland regions, upon the earth. 



INTERNATIONAL CATALOGUE OF SCIENTIFIC LITERA- 



TITPvE. 



The organization known as the International Catalogue of Sci- 

 entific Literature has by means of the cooperation of all of the 

 principal countries of the world been publishing since 1901, in seven- 

 teen annual volumes, a classified author's and subject index catalogue 

 of the current scientific literature of all the civilized countries of the 

 world. Each country collects, indexes, and classifies the scientific 

 literature ]")ublished within its borders and fui-nishes to the central 

 bureau in London the material thus prepared for publication in the 



