Physics 535 



and diffraction, the solar spectrum, etc., with a good account 

 of different theories of light. The Report for 1864 contains 

 Delaunay's classical essay on the "Velocity of Light," the 

 translation having been made by Professor A. M. Mayer, 

 then professor of physics in Pennsylvania College, Gettys- 

 burg. The experiments originally projected by Arago to 

 determine the velocity of light, and to settle some controver- 

 sies regarding the undulating theory, realized so completely 

 by Fizeau and Foucault, are here set forth so perfectly, in a 

 translation so vigorous, that no physicist can fail to acknow- 

 ledge an indebtedness to the Institution for such an admirable 

 reproduction. In 1866 there appeared an important lecture by 

 Mr. Huggins, on the " Results of Spectrum Analysis Applied 

 to the Heavenly Bodies." This was, in a sense, the beginning 

 of the New Astronomy, in the promotion of which the Institu- 

 tion has been so active in recent years. Mr. Huggins's lec- 

 ture is a clear presentation of the wonderful discoveries which 

 so rapidly followed the beautiful researches of Kirchhoff and 

 Bunsen. He refers to the assumption, based on a single 

 analogy only, that the fixed stars are essentially similar to 

 the sun, and explains that the new analysis furnishes, for the 

 first time, some decisive proof of this. The principal conclu- 

 sions reached regarding the structure, material elements, color, 

 brightness, etc., of the stars, the nature of nebulae and comets, 

 and the possible cause of variable stars, are summarized in a 

 series of propositions which make one marvel at the rapidity 

 with which the new science had grown. The Report for 1877 

 contains an exhaustive and most timely article on " Color 

 Blindness in its Relations to Accidents by Rail and Sea," 

 translated and somewhat abridged from the French transla- 

 tion of the original paper by F. Holmgren, of the University 

 of Upsala, Sweden. There is also an article on the same 

 subject by Professor Henry. 



