OF ARTS AND SCIENCES : JANUARY 29, 1873. 501 



future communication, to offer to the American Academy some results 

 of permanent value obtained by means of the instruments which could 

 not have been supplied but through its generous aid. Only the in- 

 tense application required for the zone-observations delays at present 

 those upon the physical character of the stars whose positions we are 

 determining. 



With great respect, I am, dear sir, 



Your obedient servant, 



B. A. Gould. 



The Treasurer stated that he had received $ 573, (the value 

 in currency of $500 in gold,) returned by Dr. Gould to the 

 Academy for reasons fully explained in his letter. 



Professor J. M. Crafts described a series of tests recently 

 made at the Institute of Technology, on the solubility of sul- 

 phide of arsenic in free chlorohydric acid, and on the fire-proof 

 qualities of a concrete. 



Professor Wolcott Gibbs announced that he had found that 

 the higher alkaloids, strychnin, brucin, etc., form, with the phos- 

 phates and arsenates of uranium and of the metals of the 

 magnesian group, well-defined salts corresponding to the well- 

 known ammonio-magnesic phosphate and arsenate. Many of 

 these salts yield splendid crystals, which promise to extend our 

 power of separating the different alkaloids from each other. 

 The uranic salts are remarkably insoluble, and will probably 

 yield quantitative methods of analysis. 



Dr. J. B. S. Jackson exhibited two photographs of the pre- 

 sumed fossil human skeleton lately exhumed at Mentone. He 

 also exhibited a specimen of a urinary calculus, cut in two and 

 polished to show its internal structure. 



Six hundred and fifty-third Meeting. 



January 29, 1873. — Stated Meeting. 



The President in the chair. 



The Corresponding Secretary stated that the list of Resident 

 Fellows exceeded in number that allowed by the charter, and 



