SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 87, NO. 10, PL. 2 



Z600 Z800 3000 3Z00 



I i t 



I. P>lack plate showins' results of exposures of eighteen hours' and three 



hours' duration. 



Z600 ZSOO 3000 izoo 

 J I I I I I I 



2. Composite <.if color plates showinu results of exposure of twenty-one 



minutes' flm'atimi. 



ALGAL Spectrograms 



