TLATE XIII. 



TWs i)hoto£:raph, which ivi)rpseiits tho liiiili-level cah-iiim vajwr. should he 

 coailiared with tigs. 1 and 2, IMate X. It will he seen tliat at this level the 

 penunilira is almost eonipletely covered, while many of the smaller spots are 

 lilotted out. There are also distinct evidences of dark floceuli. due to ahsorbing 

 vapors at still his/her levels. The illustration necessarily fails to indicate the 

 brilliancy of the hrit^hlest eruptive phenomena, which on the original negatives 

 are easily distinguished from the ordinary tiocculi. 



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