Chemistry and Physics. 457 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PuHysliIcs. 
nm the sensitiveness to light of the haloid salts of silver, and 
the sasdeotitn between optical and chemical absorption of light. 
—Scuurrz-Se.iack has published with the above “title a very in- 
teresting memoir, the principal results of which are, in the author’s 
words, as follows 
"In the case of a mixture of chlorine and hydrogen the curve 
of the chemical intensity of the spectrum which shows the relative 
chemical action which the different ee exert when completely 
absorbed, has a course different from that of the curve which 
rae 
citenent extends in the case of chloride of silver from ie tra- 
violet o 8HG: in the case of iodide of silver to }$ e case 
of Brarioe of silver to 4 GF, with iodo-bromide ‘and iodo-chloride 
of silver to beyond E. 
(3.) The dark a. of haloid salts of silver exposed to the 
spectrum takes place in the case of chloride of silver within the 
extent of the photographs es ; this is pee also the 
case with the other haloid sal 
4.) In the case of the haloid salts of a. the i te of 
is never zero. 
(6.) A thin film of iodide of silver absorbs the light which is 
more refrangible than G very strongly, the light between G and 
+GF but feebly; this last is, however, photographically active. 
In photo: aphing upon iodide of silver, the interposition of a thin 
film of the iodide yor like illumination with light approximately 
homogeneous from G to 1 GF. 
© 47.) Ata ae temperature the co 
a silver becomes deep brown. Th 
loration of the haloid salts 
an ee to light then 
strongly refrangible rays of the spectram } 
tion then that EE aie taciens sensitive to Tight specially a 
precisely these rays.— Pogg. Ann., exliii, p. 1 
2. On th the proteine series. melas ETZ aa “Han ERMANN have 
taken up the study of this somewhat megpected subject, and have 
arrived at results of much interest. e authors in the first p 
pass in review the results obtained many years since by wait i! 
of the products of the action of various reagents upon mem 
is othies ee 
