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Physics and Chemistry. 107 
the non-luminous flame. Variations in the thickness of the plates of 
platinum employed made no sensible difference in the heat radiated, pro- 
vided that the plates had the same diameter. When the plate of plati- 
hum was covered with carbonate of i ina 
remarkable degree, being one-half greater than that of the plate alone. 
The quantity of heat radiated was still further increased when, in addition 
to the covered platinum plate, the flame contained soda vapor arising 
from a little soda placed below the plate in the flame and not itself 
radiating heat to the pile. Under these circumstances the covered plate 
Strontium and lithium behaved like salts of sodium. These experiments 
Show that gaseous bodies radiate very much less heat than solids or 
coil, the spark exhibits in the spectroscope five new lines in addition to 
the well known ‘characteristic green line, The new lines are a very feeble 
atmosphere of hydrogen, excepting the weakest, but they were in this 
id somewhat less that of lead.—Phil. Mag., XXxvi, 223. W. G. 
3. On the photographic transparency of various bodies, and on the 
Photographic effects of metallic and other spectra obtained by means of the 
electric spark.— W. A. Mitter has published an interesting paper u 
luminous rays y reatly in permeability to the chemical rays. 
(2) Diactinic sctids (that nf say, solids which are permeable to the 
chemical rays) preserve their diactinie power both when liquefied and 
When converted into vapor. ; = 5 
_ (8.) Colorless solids which are transparent to light, but which exert a 
considerable absorptive effect upon the chemical rays, preserve their ab- 
Sorptive power with greater or less intensity both in the liquid and the 
4seous state, 
% These conzlusjons are equally true as regards liquids, whether the 
