If80' Scientific Inteltigence. 
tation on the Inflexion of Light, and has discovered many cu- 
rious phenomena which have escaped the notice of aJl preceding 
philosophers. His experiments, indeed, were made on a scale, 
and with an apparatus much larger, and more accurate, than 
had hitherto been employed. The repetition of his experiments 
will- be a matter of some difficulty, as it requires the best in- 
struments, and the nicest precautions to develope the very re^ 
markable spectra which he discovered to be produced by the in- 
flexion of light passing between wires, or transmitted through 
one or more apertures arranged in diffierent forms. 
17. Phosphorescence of' the Sulphates of Quinina and Cin- 
cEonina. — M. Callaude has found, that this substance becomes 
luminous when exposed to a gentle heat. M. Pelletier has like- 
wise discovered, that sulphate of einchonina, both alone and when 
mixed with the sulphate of quinina, become luminous when ex- 
posed to the steam of boiling water ; but that neither quinina 
nor einchonina by themselves, nor their acetates, possess the 
property of being phosphorescent by heat. Joufn. de Pharma- 
cie, Sept. 1821. 
18. Singular effect of Heat on the Spinelle of Ceylon and 
Aher. — M. Berzelius, in his very interesting and valuable work 
on the Blowpipe, just translated by Mr Children, has remarked, 
that the spinelle becomes brown by heat, and then blackens and 
becomes opaque as the heat increases. It then resumes its 
colour in cooling, in the following manner r When seen by day- 
light, its colour, by transmitted light, is a fine chrome green, then 
it becomes colourless, and finally resumes its red colour. This 
result has such a general resemblance to that obtained from the 
corundum ruby that the two minerals used may be supposed to 
have been the same. This, however, was not the case, as the 
ruby employed by Dr Brewster was a doubly refracting crystal 
with one axis. M. Berzelius does not seem to have observed' 
any peculiarity in the action of heat upon the corundum ruby. 
See Berzelius, He VEmploi du Chalumeau, p. 289, 252. 
ACOUSTICS 
19. On Sounds excited in Hydrogen Gas, — As the intensity 
of sound is diminished by the rarefication of the medium in 
See this Journal.^ Vol. VI, p, 379!. 
