176 MINUTES. [Dec. 20, 1901. 



We may conclude, I think, that the cloud formation had dissi- 

 pated at some time between the 8th and the 12th. 



18. The season of the martian year at which these clouds occur- 

 red is of interest. On December 7, 1901, it was April 26 in the 

 northern hemisphere of Mars. The suri had gone north of the 

 equator and was then overhead on the fourteenth parallel of latitude. 

 The heat equator was a little behind it. Apparently then a current 

 bearing the clouds was setting toward the heat equator from within 

 the tropics to the south, where the season corresponded to the end 

 of October. This current was deflected some eighty degrees to 

 the east, and became an east-by-north wind. 



19. Its origin may have been local. A little to the south of where 

 the cloud first appeared lies the long east-and-west stretch of the 

 Sabaeus Sinus or Icarium Mare. Now the form of the cloud was 

 of the same general shape — a cloud stretching east and west five 

 times as far as it did north and south. The Icarium Mare is 

 undoubtedly a great tract of vegetation, where moisture would be 

 held and whence it could accordingly be given off. Arising there, 

 either from seasonal or temporal cause, the vapor would gather into 

 a cloud and proceed to float away over the desert regions to the 

 north. If this, then, is what happened in the case before us, we 

 may conceive the cloud as having been generated on the 6th of 

 December over the Icarium Mare, rising to a height of thirteen 

 miles, and then traveling east by north at about twenty-seven miles 

 an hour off into the desert of Aeria, there to dissipate after an 

 existence of three or four days. That it was a phenomenon of 

 capricious not of regular production is shown by its not having 

 been repeated — that is, it partook of the subtle unpredicability of 

 cloud. 



Stated Meeting, December 20, 1901. 



Vice-President Sellers in the Chair. 



Present, 30 members. 



Mr. C. Stuart Patterson read a memoir of the late Hon. 

 Frederick Fraley, LL.D., President of the Society. 



The meeting was adjourned by the presiding officei. 



