2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 95 



three-fourths the Earth's distance from the Sun. If such should 

 prove to he the case, the visible spottedness of the Sun should be 

 decreased when Venus and the Earth are on the same side of the 

 Sun, or increased when they are on opposite sides, or both phenomena 

 should appear. 



In the publications of The International Astronomical Union are 

 given the daily values of the sun-spot relative numbers beginning with 

 191 7. The mean sy nodical period of Venus is 584 days. The daily 

 sun-spot numbers for 10 synodical periods of Venus, beginning at 

 superior conjunction of Venus and the Sun on April 25, 191 7, and 

 ending June 29, 1932, w-ere arranged in regular order in their respec- 



Average value at superior conjunction, 68L 

 Average value at inferior conjunction, 385. 



tive periods and their average values for the lo synodical groups were 

 determined. The actual values for 5 days, 2 days before and 2 days 

 after the day of conjunction, for the 10 superior conjunctions and the 

 10 inferior conjunctions of the 5,840 days under consideration, are 

 given in table i. 



It will be seen from the above table that the sun-spottedness was 

 76.9 percent greater when Venus and the Earth were on opposite sides 

 of the Sun than when they were on the same side. In the actual days 

 of conjunction this difference is 80 percent. 



During the 10 synodical periods of Venus there were 20 days 

 when Venus and the Earth differed in heliocentric longitude by 90 

 degrees. Five days were taken at each of these periods — 2 days be- 

 fore and 2 after the exact' day on which Venus and the Earth were 



