106 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



vations upon a black (untreated) carbon at temperatures ranging between 

 795° C and 1055° C. In tbis diagram abscissae are wave lengths and 



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I 



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T 



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~/ T 



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Figure 18. 



IIOO' 



ordinates are ratios of the brigbtness of the spectrum of tbe carbon rod 

 in each region to that of the corresponding region in the spectrum of 



