ACADEMY OF SCIENCES. 147 



here from the Gulf, but did not attach much importance to them. 

 He did not know that the object seen by himself and others was a 

 ship, but he thought it was ; and because he had seen it on several 

 occasions, he knew it could not be the effect of mirage. Neither 

 could it be the schooner said to have been hauled to the desert on an 

 ox-cart by Martin Vise, for that went by a road far south of the 

 place described, and he had reason to believe it had reached its 

 destination, and was now afloat. Furthermore, the supposed ship 

 was described before Vise ever started with his schooner. He 

 mentioned one person who claimed to have gone to it and examined 

 it, and who said it was made of teak wood. 



Some conversation followed in regard to cloud-bursts and their 

 effects. 



Prof. Davidson commented on the unreliability of the barometer 

 for observations of heights in the heart of a continent. 



Col. Williamson gave his views on the same subject, and thought 

 one portion of the Colorado desert might be as low as has been re- 

 ported. 



The thanks of the Academy Avere returned to Col. Evans for his 

 interesting communication. 



Regular Meeting, December 5th, 1870. 

 President in the Chair. 



Donations to the Cabinet : A spider, allied to the genus Gastro- 

 ca7ithus, from San Rafael, by Henry High ton, through the Presi- 

 dent. A white magnesian mineral from Market Street Cut, by Dr. 

 Cooper. 



Prof. Davidson presented some specimens of oysters raised in 

 San Francisco Bay, from seedlings brought from New York, 

 and planted in March last, showing a very rapid growth. They 

 were several times larger than the seedlings. 



Mr. Throckmorton, Dr. Cooper and others, said that shells of this 

 size were three years old in New York Harbor, and doubted their 

 growing here in the time stated ; but Prof. Davidson said the 

 fact was from undoubted authority. 



