PREFACE. 



This bibliography, haviui^ for its object the scientific aspects of the 

 chemical influence of light, the practical applications, including that of 

 Photography, are nearly all omitted, as has been the case in my previous 

 works of this kind. 



An index to the literature of Photography is being prepared under 

 the auspices of the Committee for Indexing Chemical Literature, of the 

 American Association for the Advancement of Science. 



Alfred Tuckerman. 



Newpout, K. I., 



April, 1891 



(iii) 



