TO CORRESPONDENTS. 



JVew Experiments on the Solar Spectrum. — We are obliged to omit, for want of 

 room, a paper by Prof. Olmsted, describing a series of very beautiful experiments 

 on the colors of the solar spectrum, first performed by Mr. Forrest Shepherd. 

 The communication will appear in our next number. 



Papers, "on the analysis of the Coprolites of Birds," by Dr. S. L.Dana, and *• Ob- 

 servations upon the Valley of the Jordan and the Dead Sea," by Mr. J. D. Sher- 

 wood, will have an insertion in the January No. ; and also communications from 

 Prof. Strong, Prof. Bailey, Mr. J. D. Dana, and Prof Dewey. 



Authors' Copies of Communications. — We wish it understood that twelve copies 

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