316 Dana on the relations of Death to Life in Nature. 



of reflections from curved surfaces, and, in particular, the images 

 from concave surfaces. 



During the last year or two large assemblages have been 

 drawn together in our principal cities, to see with delight the ef- 

 fects produced by what is called the Stereopticon, which is merely 

 another name for a Magic-lantern of good quality, with one side 

 of a glass stereograph for a slide. Nearly all in these large as- 

 semblages have agreed in believing that they saw, what they 

 were told they saw, excellent stereoscopic effect in the single 

 picture which alone is exhibited. The truth is they made the 

 popular mistake ; they saw nothing but perspective. 



Stereoscopic effect on a large scale may be obtained by exhib- 

 iting the right and left pictures of a glass view side by side, by 

 the magic-lantern, and then uniting the magnified pictures by 

 means of prisms. This I have recently demonstrated by exper- 

 iment. The idea was also suggested some years ago, by Dr. 

 Wolcott Gibbs to Mr. Pike, of New York, but not put to the test. 



We conclude, then, from the foregoing— 



1. That Prof. Cima's experiment is only another instance 

 showing how easily we can mistake one thing for another, and 

 induce others to do the same. 



2. That intuitive perception of relief may be indefinitely 

 increased in degree by exercise ; showing that this sense follows 

 the same law under which we employ our other faculties. 



The 



of a plant with " seed in itself," as Moses 

 states in his concise description, was the simultaneous institution 

 of life and death. It was the establishment of an incoming and 

 outgoing stream, to be in constant flow as long as the kingdoms 

 of life should last— an incessant renewal of youth, and rejec- 

 tion of age. 



All life is a system of progressing change in cycles— the genn 

 first, then the embryo, the young, the adult, and last, the seed 

 or germ again, to continue the rounds ; the adult sooner or 



* From a paper on the Anticipation of Man in Nature, published in the Ne^r 

 Englander, for May, 1859. Views similar to those here given on stored force in pla^J 

 Td pSshed il' Jhr9^rmal"fi''°''''"°° '° ^"^■' ' ^^ ^■^^' ^iT A^ S' 



Dana's paper is prior in date, he will not be charged With copying the views (wluj 

 Kx 32°°\r^''^ independent,) of Prof. LeConte. The paper of Prof. Henry,_ ^^^^ 



