Awakens tJie Interest of Scientific Me7i. 23 



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human intervention, the trees having been cut away 

 and destroyed, thus allowing the rains to wash down 

 quickly, leaving the island almost sterile in parts. 



Many expeditions were made over the island : one 

 to the town of Ribeira Grande, where a fine old 

 ruin, a cathedral and fort were found, the former 

 containing many objects of interest dating back to 

 the sixteenth century. The dignitaries of the church 

 were buried here, and Darwin noticed one tombstone 

 which bore the date 1497, five years after the discov- 

 ery of America, and three after that of the islands. 



The atmosphere of St. J ago was, as a rule, hazy, 

 and here our young naturalist made some observa- 

 tions which created much interest among scientific 

 men. Investigation showed him that the haze, 

 which often obscured the mountains, was occasioned 

 by a fall of dust so impalpable and fine that it 

 rested in the air as haze or a very light fog. Some 

 of this was collected and sent back to Professor 

 Ehrenberg for examination, and in 1845 Darwin 

 forwarded an elaborate paper on the subject to the 

 Royal Geographical Society. The dust in some 

 places was offensive, covering every thing and soil- 

 ing the sails and clothing of the men. 



In the course of the voyage pieces larger than 

 the thousandth of an inch square were noticed. 

 Whence came this strange shower? was the ques- 

 tion he wished to solve, and the problem could only 

 be answered by a determination of the elements 

 which composed it. This Professor Ehrenberg was 

 enabled to accomplish. He found that the dust- 

 shower did not come from the Cape Verd Islands 



