FINAL ACT OF SECOND PAN AMERICAN SCIENTIFIC CONGRESS. 187 



Costs of Primary Triangulation, Including Determinations of Latitude, 

 Longitude, and Azimuth. WILLIAM BOWIE, United States Coast 

 and Geodetic Survey. 



Work at Lick Observatory: 



(a) At Mount Hamilton, California, (b) In Chile, South America. 

 (Read by title.) W. W. CAMPBELL, Director of Lick Observatory. 



Costs of Relative Gravity Determinations by Aid of Half -second Pendulums. 

 WILLIAM BOWIE, United States Coast and Geodetic Survey. 



Progress of the Work, Optical and Mechanical, on the 72-inch Reflecting 

 Telescope for the Canadian Observatory at Vancouver. JOHN A. 

 BRASHEAR. 



Work of Mount Wilson Solar Observatory. F. H. SEARES, Carnegie Insti- 

 tution of Washington. 



Subsection B. 



FOURTH SESSION, FRIDAY, DECEMBER 31, 19152.30 P. M. 

 C. F. MARVIN, Chairman. 



Monthly Storm Frequency in the United States. C. J. KULLMER. 

 Discussion by Messrs, HENRY, ARCTOWSKI, and HUNTINGTON. 



The Thunderstorm of the United States as Climatic Phenomena. R. 



DEC. WARD. 

 Discussion by Messrs. Cox and ARCTOWSKI. 



Solar A ctivity, Cyclonic Storms, and Climatic Changes. ELLSWORTH HUNT- 

 INGTON. 

 Discussion by F. E. NIPHER. 



The Influence of the Great Lakes upon the Movement of High and Low 



Pressure Areas. H. J. Cox. 

 Discussion by Messrs. CHURCH, HENRY, and CLAYTON. 



The Duration and Intensity of Tropical Rains. O. L. FASSIG. 



