268 Mr. Hunt on Light ^hich has ^permeated coloured Media, 
riates, always keeping in view the definite proportion re- 
quired for the quantity of the nitrate of silver used ; it will be 
found that almost every variety of shade, from a rich dark 
purple to a full red, and a few other tints, may be produced 
at pleasure. 
2. The effects of light, passing through coloured glasses 
on various papers, are singularly diversified. The following 
are a few of the most striking results. (The glasses are, a 
deep cobalt blue, a full laurel green, an amber yellow, and a 
rich orange red. They are so framed that all the papers can 
be exposed at the same time to the solar influence.) 
Colour of Glass^ 
Blue. Green. Yellow. Red. 
Salt used. 
a. Chlor. of sodium. 
b. Chlor. of potassa. 
c. Muriate of lime. 
d. Muriate of iron. 
e. Mur. of peroxide 
of iron 
f. Mur. of baryta .. 
g. Muriate of man 
ganese 
h. Mur. of ammonia 
Effects produced. 
Purple. 
Blue. 
Violet. 
Chocolate. 
Light purple. 
Sky blue. 
Light violet. 
Tinted red. 
Rich violet. 
Faint blue. 
Blue. 
Reddish. 
Red. 
Colourless. 
Faint red. 
Leaden hue. 
Blue. 
Yellowish. 
Straw color. 
Yellow brow 
Purple red. 
Lilac. 
Chocolate. 
Pink. 
Rich browu. 
Reddish. 
Rose hue. 
Yellow. 
Olive brown. 
Palebrown.l Brown. 
Dull orange. 
3. I have found but a modified action from the interference 
of coloured fluids. In a few instances, under a solution of 
carmine in ammonia, I have obtained the richest crimson dye ; 
but I cannot, by any means I have used, succeed in fixing 
the colour on the paper. 
4. A paper prepared, by first washing it with a solution of 
twelve grains of the iodide of potassium in one ounce of 
water, and then with a solution of ten grains of the crystallized 
nitrate of silver in the same quantity of fluid, is very sensitive. 
When exposed beneath a solution of the ammonia-sulphate 
of copper to sunshine, it changes to a rich light blue. Acetate 
of copper produces a hromi. Muriate of the peroxide of iron 
imparts a green tinge, and solutions of carmine a brown red. 
5. The paper f becomes red, when acted on by rays pass- 
ing through nitrous acid gas, and is tinged yellow, by the light 
which has been subjected to the interference of chlorine and 
its protoxide. 
6. To have as full a volume as possible of iodine and bro- 
mine vapour, carefully closed vessels containing a small por- 
tion of these bodies, were placed upon a plate of copper 
warmed by water. 
The paper h was laid beneath them, and exposed to lumi- 
nous influence. Under the bromine it was unchanged, but 
