272 Scientific Intelligence. 
directions, as if the solid or fluid were self-luminous while under the 
influence of the incident rays. The effects produced on similar media 
lead to interesting information with respect to the nature of various 
flam s the feeble flame of alcohol is extremely brilliant with 
regard to invisible rays of very high refrangibility. o hy- 
gen appears to abound in rays of still higher refrangibility, while th 
light of the electric spark as tested by a weak solution of sul te of 
quinine, is found to be very rich in invisible rays of excessively 
high refrangibility, such as would place them far beyond the limls 
he maps hitherto made of the fixed lines in the chemical part of 
phoro-genic rays of an electric spark are nothing more than rays 
the same nature as those of light, but which are invisible and of very 
high refrangibility. If so, they ought to be stopped by a very small 
ndex of circular polarization, form part of every complete 1 ? 
: The abstract of Prob 
partly verbatim, leaves us however in doubt as to many important 
heir refrat 
or whether 
ie ams sifted through the medium which produces pyre pec 
is then capable of affecting a daguerreot late. slancesew antes © 
8 gue ype p “ it is not impossi- 
le that by a still further diminution of refrangibility, ray$ a. 
light can be converted into rays of heat.—w. G.] cademy 
2. On Heliochromics.—Nizrce has communicated to the A 
a third memoir upon this subject, which contains mapy ibe gras 
eo and bss appears to bring us nearer to the sep he Oa 
problem of photography—the production of images © ey 
natural colors. After having shown the possibility of reproducing °F 
