PHOTOCHEMISTRY. . ' 369 



grapTiic portraitures, chiefly of dolls, with tlieir colors. He did not succeed, 

 however, any more than M. Becquerel, in obtaining- a persistent image. M. 

 Poiterin has taken up the inquiry, and by means of paper rendered sensitive 

 through chloride of gold and chromic acid, has obtained colored images of quite 

 pleasing appearance, a little more durable, and which may be even preserved in 

 an album. Their preservation, however, is compatible only with a diffused light ; 

 but it is probable that ere long success will attend the efforts for perfecting this 

 part of photography. 



In concluding, I would wish to give especial prominence to the idea that, if 

 heretofore much attention has been bestowed on photography, there is still some- 

 thing' more interesting. It is the chemical action of light ; it is this transfonna- 

 tion of a certain sort of movements in a phenomenon which, until now, has been 

 considered as a mechanical one, but which enters, through these experiments, 

 into the phenomena of optics. 



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