350 PROCEEDINGS OP THE AMERICAN ACADEMY 



The new phenomenon promises to be of great assistance in 

 studying the extremities of the human body, and in detect- 

 ing the presence of metallic bodies and fragments of glass in 

 them. A shot, placed on the back of the hand, can be photo- 

 graphed through the flesh of the thickest portion of the hand. 

 Of course, therefore, it could be detected if it were imbedded 

 in the hand. 



Pictures have been taken at the Jefferson Physical Labora- 

 tory, after an exposure of one minute, which show the bones 

 of the hand, and there is no doubt that the time of exposure 

 can be reduced to a few seconds for certain portions of the 

 extremities. The Crookes tubes can be protected from injury 

 by immersing their terminals in a suitable oil, — preferably, 

 boiled linseed oil. 



The following paper was read by title : — 



On the Group of real Linear Transformations whose Invari- 

 ant is an Alternate Bilinear Form. By Henry Taber. 



Eight hundred and eighty-first Meeting. 



March 11, 1896. — Stated Meeting. 



Vice-President B. A. Gould in the chair. 



The Corresponding Secretary read letters from Carl Gegen- 

 baur, W. Kuhne, and H. Graf zu Sohns-Laubach, acknowledg- 

 ing their election as Foreign Honorary Members ; from the 

 Natural History Societ}^ of Bonn, announcing the death of its 

 Secretary, Philipp Bertkau ; from the Joint Commission of the 

 Scientific Societies of Washington, D. C, with regard to the 

 proposition for a Director in Chief of Scientific Bureaus in 

 the Department of Agriculture. 



On the motion of the Corresponding Secretary, it was 



Voted, To meet on adjournment on the 8th of April. 



W. M. Davis read a paper on the Outline of Cape Cod. 



C. L. Jackson made the following announcement : — 



C. L. Jackson and A. M. Comey have found that potassic co- 

 balticyanide is converted by boiling nitric acid into a red jelly, 

 having the formula KH.2Co,;(CN)iiH^O, from which a silver salt, 

 Ag3Co3(CN)uH20, and a barium salt, BaHCo3(CN)xiliH20, 



