284 Lieut. Maury on the Probable Belation between 



moisture, must bring the moisture with them from some sea 

 or another. 



Therefore though it may be urged, inasmuch as the winds 

 which brought the Patagonian rains came direct from the 

 sea, that they therefore took up their vapours as they came 

 along ; yet it could not be so urged in this case ; and if these 

 winds could pass with their vapours from the equatorial 

 calms through the upper regions of the atmosphere to the 

 calms of Cancer, and then as surface winds into the Missis- 

 sippi valley, it was not perceived why the Patagonian rain winds 

 should not bring their moisture by a similar route. These last 

 are from the NW., from warmer to colder latitudes; therefore 

 being once charged with vapours they must precipitate as they 

 go, and take up less moisture than they deposit. 



This was circumstantial evidence. No fact had yet been 

 elicited to prove that the course of atmospherical circulation 

 suggested by my investigations is the actual course in nature. 

 It is a case in which I could yet hope for nothing more direct 

 than such conclusions as might legitimately flow from cir- 

 cumstantial evidence. 



My friend Lieut. De Haven was about to sail in command 

 of the American expedition in search of Sir John Franklin. 

 Infusoria are sometimes found in sea-dust, rain-drops, hail- 

 stones, or snow-flakes ; and if by any chance it should so turn 

 out that the locus of any of the microscopic infusoria which 

 might be found descending with the precipitation of the 

 Arctic regions should be identified as belonging to the regions 

 of the SE. trade winds, we should thus add somewhat to the 

 strength of the very slender clue by which we were seeking 

 to enter into the chambers of the wind and to " tell whence 

 it cometh and whither it goeth." 



It is not for man to follow the " wind in his circuits,'* and 

 all that could be hoped, was, after a close examination of all 

 the facts and circumstances which these charts have placed 

 within my reach, to point out that course which seemed to 

 be most in accordance with them, and then having established 

 a probability or even a possibility as to the true course of 

 atmospheric circulation, to make it known and leave it for 

 future investigations to confirm or set aside. 



