166 ANNUAL OF SCIENTIFIC DISCOVERY. 



remarks, of no peculiar moment, M. Niepce de Saint- Victor informs 

 us, that the colors are rendered very much more vivid by the action 

 of ammonia, and at the same time this volatile alkali appears to fix the 

 colors with much permanence. These results bring much more near 

 than hitherto the desideratum .of producing photographs in their 

 natural colors. The results are produced upon plates of silver which 

 have been acted upon by chloride of copper, or some other combina- 

 tion of chlorine. 



M. Niepce stated a curious fact, namely, that the colors become 

 more rapidly effaced by the light in the mornings than in the after- 

 noons. In connexion with this subject, it may be mentioned that 

 there have been presented to the Academy a number of lithographic 

 designs on sheets of gutta-percha, pressed as thin as ordinary letter 

 paper. 



The following remarks upon the above announcement are taken 

 from the Paris Journal, " Cosmos." 



Formerly, for fixing the colors, M. Niepce de St. Victor operated 

 by means of contact, that is to say, he placed on the chlorided plate 

 the painted image that he wished to copy. The colors were Outward ; 

 the luminous rays in passing through them were in their turn colored, 

 and shaded the plate by exercising on it their photogenic action. It 

 is therefore certain that hitherto, M. Niepce had operated only on flat 

 objects by means of contact, and not at a distance without the aid 

 of a camera. 



These conditions for success appeared so essential for the produc- 

 tion of colors, that very skilful practitioners doubted obtaining any 

 thing more. Indeed, we have been told that M. Regnault had chal- 

 lenged M. "Niepce ever to succeed in obtaining the colored image of a 

 boquet of flowers. The challenge was accepted, and much has been 

 accomplished. M. Niepce took a bouquet of hollyhocks with its 

 leaves, flowers and buds ; he filled up the empty parts with vine 

 leaves, suspended the bouquet in the air, directed his camera towards 

 it, received its image on the chlorided plate, and before hah an hour 

 had passed, the buds and flowers red, rose-color and yellow, &c., had 

 painted themselves with their various shades quite discernible, and we 

 have seen, ourselves, these encouraging proofs. The leaves alone, 

 particularly the vine leaves, of a dark green, remained refractory ; 

 their forms were depicted black. This negative result will not astonish 

 any one, for every one knows that the photogenic action of green rays 

 is almost nothing ; it is not however entirely so, and every thing leads 

 us to hope that success will be obtained in overcoming this difficulty. 

 Before operating with a bouquet, INI. Niepce had operated with figures, 

 with a colored bust of the Prince President, and had obtained proofs 

 really perfect, in the camera, with the perfect outline that flat pictures 

 did not give. 



The reason of M. Regnault's imagining that it would be fruitless to 

 copy the natural colors of bodies, such as flowers, for example, was 

 this ; he considered them too much weakened, or diluted with white 

 that the prominent influence of the white light would destroy the tint, 



