1032 Transactions of the A3terican Institute. 



astronomers were probably due to the refraction prodaced by the 

 earth's atmosphere. The luminous portion of the moon immedi- 

 ately surrounding the dark portion, is made visible by the solar nxys 

 which have passed through our atmosphere to the moon and then 

 reflected towards us, in the com'se of which the actinic power of 

 the ray is neutralized. 



Mr. H, T. Anthony then stated some facts in relation to the sanie 

 «ubject; after which 



Prof. Joy presented for inspection a fine collection of views taken 

 on the coast of Labrador, by Mr. J. Dunmore. The prints were 

 highly commented upon. 



Prof. Joy also presented a communication from Mr. J. Johnson, 

 Saco, Maine. 



Mr. i^, Wilson, of Philadelphia, presented a very large and fine 

 collection of carbon prints, which were made in France, by Swan's 

 process. The prints were mounted on a variety of difierent colored 

 papers. 



The thanks of the members were tendered to Mr. Wilson. 



Mr. Newton gave a very minute and detailed account of the 

 mode of making the photographs which were exhibited at the last 

 meeting. 



The Section then adjourned to the first Tuesday in March. 



March 3, 1868. 

 Prof. S. D. Tillman in the chair; 0. G. Mason, Secretary. 



Minutes of the last meeting were read and approved. 



In answer to a question upon the refraction and reflection of 

 light, Prof. Vanderweyde stated that the light of the sun was 

 refracted by the atmosphere of the earth, as it would be in passing 

 through a globe lens, and by which a portion of the actinic force 

 was absorbed. The luminous portion sufiered less obstruction, 

 and therefore, when reflected, as from the surface of the moon, 

 might appear in excess. This was made apparent by photographs 

 of the moon, the actinic force outside the visible image being suflfi- 

 cient to produce an impression longer than that formed by the 

 luminous rays; therefore, in such photographs we see more of the 

 sm-face of the satellite than we should with the unaided eye, or 

 through the telescope. 



