208 Hi. C. Bolton—Action of Light on Uranium. 
Burnett’s, and obtained a patent for them in February, 1858. 
We have no evidence that Niepce de St. Victor was ignorant 0 
Burnett’s invention. Credit, however, is due to him for an ex- 
perimental illustration of the remarkable property possessed by 
nitrate of uranium of absorbing actinic rays of light, and re- 
taining them in an active condition for a long time. . He ex- 
posed behind a negative, paper strongly impregnated with ni- 
trate of uranium, and then hermetically sealed it in metallic 
tubes. This paper retains the power of darkening chlorid of 
silver, for weeks and even months. On opening a tube, and 
placing the paper on a sensitive surface, an image is obtained 
identical with that of the negative employed. 
In the following year, Niepce de St. Victor, together with 
Corvisart,* discovered that the presence of a small quantity of 
nitrate of uranium increased ten-fold the action of light on 
amylaceous matter, converting it into dextrine and glucose. 
They also remarked the decomposition of oxalic acid in pres- 
ence of nitrate of uranium, with formation of carbonic acid. 
Corvisart’s last-mentioned experiment was repeated by See- 
kampy with greater accuracy; he employed solutions con- 
taining 5 per cent oxalic acid, and 1 per cent oxalate of ura- 
nium ; 100 c.c. of this solution, exposed to light for three 
minutes, furnished 22 c. c. of gas, which consisted of carbonic 
oxyd and carbonic acid. Seekamp observed the formation of 
crystals of oxalate of the protoxyd, and determined the pres- 
ence of formic acid in the solution. The same chemist subse- 
quently examined the action of light on the succinate and 
pyrotartrate of uranium.{ The succinate acid is converted in- 
to propionic acid, and the pyrotartaric into butyric. A de- 
but two or three years afterward when the process became 
known by the publication of the specification, its value was 
found to be exaggerated. : 
phite of soda were employed and the only novelty consisted 2 
* Compt. Rend., xlix, 368; also Bull. Soc. Chim., 1862, 62. 
Ann. Chem. Pharm., exxii, 113. + Ann. Chem. Pharm., exxxiii, 253. 
foe Bee. Belge de Phot., 1864. Original announcement in Horn’s Photog. Journ. 
: CeCe 
