352 PROCEEDINGS OF THE AMERICAN ACADEMY 



Eight hundred and fiftieth Meeting. 



May 11, 1892. — Social Meeting. 



The Academy met at the University Museum, Cambridge. 



The President in the chair. 



The President announced the death of August Wilhelm 

 Hofmann, of Berlin, Foreign Honorary Member of the Acad- 

 emy, and gave a brief sketch of his scientific work. 



The following papers were read : — 



Biographical Memoir of the late Sereno Watson. By 

 George L. Goodale. 



On Bivalent Carbon. By John U. Nef. 



Diamonds in Meteoric Iron. By Oliver W. Huntington. 



The mineral cabinet of Harvard College was fortunate enough to 

 obtain, through the liberality of Francis Bartlett, Esq., one of the 

 two original masses of meteoric iron, weighing 154 pounds, brought 

 by Dr. A. E. Foote from near Canon Diablo, Arizona. As this iron 

 had been said to contain diamond, the following experiments were 

 made with a view of isolating if possible the diamondiferous material. 

 A mass of about one hundred grams' weight was dissolved in acid 

 assisted by a battery. 



The iron was supported on a perforated platinum cone hung in a 

 platinum bowl filled with acid, and the cone was made the positive 

 pole and the dish the negative pole of a Bunsen cell. When the iron 

 had disappeared, there was left on the cone a large amount of a black 

 slime. This was repeatedly washed and the heavier particles col- 

 lected. This residue examined under a microscope showed black and 

 white particles, the black particles being mainly soft amorphous 

 carbon, while the composition of the white particles appeared less 

 easy to determine, though when rubbed over a watch-glass certain 

 grains readily scratched the surface. 



The material was then digested over a steam bath for many hours 

 with strong hydrofluoric acid, and some of the white particles disap- 

 peared, showing them to have been silicious. Most of them, however, 

 resisted the action of the acid. These last were carefully separated 

 by hand, and appeared to the eye like a quantity of fine white beach 

 sand, and under the microscope they were transparent and of a bril- 

 liant lustre. A single particle was then mounted in a point of metal- 

 lic lead, and when drawn across a watch-crystal it gave out the 

 familiar singing noise so characteristic of a glass-cutter's tool, and 



