reactions on silver
with the microcosmic bead and copper salt as the metallic chlorides.
The purplish color which, however, characterizes the chlorides, is
more inclined to greenish with the bromides. If the substance be
placed in a flask or glass tube, and fused with bisulphate of potassa,
over the spirit-lamp, sulphurous gas and bromine will be eliminated.
Bromine will be readily detected by its yellow color and its smell.
Bromine may be readily detected by passing a current of chlorine
through the fluid, after which ether is added and the whole is
agitated. The ether rises to the top, carrying with it the bromine in
solution; after being withdrawn, this ether is mixed with potassa, by
which the bromide and bromate of potassa are formed. The solution is
evaporated to dryness, the residue is fused in a platinum vessel, the
bromate is decomposed, while the bromide remains; this must be
distilled with sulphuric acid and the binoxide of manganese. A red or
brown vapor will then appear, indicating the presence of bromine; this
vapor will color starch paste--which may be put in the receiver on
purpose--of a deep orange color.

If, to a solution containing a bromide, concentrated sulphuric or
nitric acid be added, the bromine is liberated and colors the solution
yellow or red. The hypochlorites act in the same manner. The bromine
salts are coming into use extensively in photography, in consequence
of their greater sensitiveness to the action of light than the
chlorides alone.

(10.) _Iodine_ (I).--This element occurs in salt-springs, generally
combined with sodium; it also exists in rock-salt; it has likewise
been found in sea-water, also in a mineral from Mexico, in combination
with silver, and in one from Silesia, in combination with zinc. As
sea-water contains iodine, we would consequently expect to find it
existing in the sea-weeds, and it is generally from the ashes of these
that it is obtained in commerce.

When the metallic iodides are fused with the microcosmic salt and
copper, as previously indicated, they impart a green color to the
flame. This color cannot be mistaken for the color imparted to the
flame by copper alone. When the metallic iodides are fused in a glass
tube, closed at one end, with the bisulphate of potassa, the vapor of
iodine is liberated, and may be recognized by its characteristic
color. Those mineral waters containing iodine can be treated the same
as for bromine, as previously indicated,