186 PROCEEDINGS OF THE AMERICAN ACADEMY 



ulars concerning these Medusa-like forms, which he proposed 

 to embody in a paper to be presented at a future meeting. 



Professor W. B. Rogers made a communication on the sub- 

 ject of binocular vision, giving his own explanation of the 

 phenomenon, and illustrating it by the aid of the stereoscope. 



This communication was followed by remarks from Pro- 

 fessor Agassiz, Dr. Pickering, Dr. W. F. Channing, and the 

 President, on various phenomena connected with the laws of 

 vision. 



Dr. Durkee exhibited filterings from the water of a lake in 

 Haverhill, showing animal forms containing oil, similar to 

 those found in Cochituate water at the present time. 



Foui' Iiundred and eleventli meeting. 



February 13, 1855. — Monthly Meeting. 



The President in the chair. 



Mr. G. P. Bond presented, in behalf of W. H. Emory of 

 the U. S. Topographical Engineers, a paper, entitled, 



" Discussion of Observations for the Isodynamic, Isogenic, 

 and Isoclinal Curves of Terrestrial Magnetism on and near 

 the Line of the Boundary Survey between the United States 

 and Mexico, made in 1849, 1850, 1851, and 1852, under the 

 Orders of Major W. H. Emory, Astronomer of the Boundary 

 Commission," — being a continuation of the article on the 

 same subject in Volume V., page 1, of the Academy's Memoirs. 

 Mr. Bond also exhibited some diagrams of the planet Sat- 

 urn, and mentioned various facts concerning it ; namely, that 

 the inner edge of the rings is constantly approaching the 

 planet itself; that the ball is seen through the rings, which 

 are consequently transparent ; that the color is different in 

 different parts of the rings, the equatorial regions being white, 

 the temperate region reddish, and the polar bluish. He also 

 mentioned that the shadow of the ball upon the ring can be 

 seen on both sides of it, being on one side rather faint, but on 

 the other quite decided. This anomalous appearance he first 



