PHILOSOPHICAL SOCIETY OF WASHINGTON. 185 



Mr. J. E, HiLGAKD exhibited and described an 



"OPTICAL SALINOMETEE," 



consisting of a prism to contain a saline solution, and a telescope 

 and micrometer tor measuring changes in the index of refraction, 

 as the strength of the solution is changed. He claimed for it 

 great delicacy and adaptation to use at sea, as it would not be 

 affected by the motion of the vessel. 



Remarks were made by Messrs. Dutton and Antisell. 



• Mr. J. M. Toner exhibited a malformed dog, only a few days 

 old, which Mr. VVoodwaed described as a monstrosity in excess; 

 the forward portion being single, while from the waist down it 

 was a pair of twins. The middle leg, however, comprised a right 

 and left leg united under the same integument, and he supposed 

 that the tail would also, on dissection, be found double. He then 

 referred to the case of a Portuguese man, well known to the 

 medical profession, and to a recent paper by Rauber.* 



Prof. James D. Butler, of Madison, Wisconsin, made a com- 

 munication on 



PREHISTORIC copper, 



exhibiting a variety of copper implements found in Wisconsin, a 

 few feet below the surface, and describing their uses and the 

 localities from which they were obtained. 



Remarks were made by Messrs. White and Gilbert, chiefly 

 on the copper drifts in Iowa and Missouri, derived from the 

 copper region of Lake Superior; by Mr, Dall on the copper 

 implements made and used at the present time in Alaska ; by 

 Mr. Powell on similar implements of stone made and used by 

 other tribes in North America, and by Mr. Mason on the many 

 mounds in the region described by Mr. Butler. 



* Die Theorin der excessiven Monstra. Vikchow's Archiv, Bd. 71, 

 1877, S. 137. 



