AMERICAN JOURNAL 
SCIENCE AND ARTS. 
CONDUCTED BY 
BENJAMIN SILLIMAN, M.D. LL. D. 
Prof. Chem., Min., &e. in Yale Coll.; Cor. Mem. Soc. Arts, Man, and Com.; and 
For. Mem. Geol. Soc., London; Mem. Roy. Min. Soc., Dresden; Imp. 
Agric. Soc., Moscow; Hon. Mem. Lin. Soc., det Nat. Hist. 
Soc. Belfast, Ire.; Phil. and Lit. Soc. Bris 1 ia -$ 
Mein. of various Lit. and Scien. Soc. Ragas 
VOL. XX. JULY: 1631. 
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Penge 
NEW HAVEN: 
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