TliK CENTURY'S PROGRESS IN CHEMISTRY 



tention. In the same year Mr. Fox Talbot read a paper 

 on the subject before the Koyal Society, and soon after, 

 wards the efforts of Herschel and numerous other natu- 

 ral philosophers contributed to the advancement of the 

 new method. 



JOHN W. DRAPER 



In 1843 Dr. John W. Draper, the famous English- 

 American chemist and physiologist, showed that by 

 photography the Fraunhofer lines in the solar spectrum 

 might be mapped with absolute accuracy ; also proving 

 that the silvered film revealed many lines invisible to 

 the unaided eye. The value of this method of observa- 

 tion was recognized at once, and, as soon as the spectro- 



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