Chloride of Bromine.—Formed by transmitting a current of chlorine through bromine, and condensing the disengaged vapors by a freezing mixture. The factitious article is more simply formed, and is equally good as an accelerator, but not as quick. See page 25, Part I. M. Bissou, a Frenchman, found that the real chloride of bromine is so sensitive, that Daguerreotype proofs are taken by it in half a second. He succeeded in taking persons and animals in the act of walking.
Bromic Acid may be obtained by pouring sulphuric acid upon a dilute solution of bromide of baryta, and evaporating. No interest.
Bromide of Baryta.—Boil of protobromide of iron with moist carbonate of baryta; carefully evaporate and it will crystallize in white rhombic prisms, which have a bitter taste, are slightly deliquescent, and soluble in water and alcohol.
Bromide of Carbon.—Formed by mixing one part of periodide of carbon with two of bromine. Two compounds are formed, the bromide of carbon, and the sub-bromide of iodine; the latter is removed by a solution of caustic potassa. It is liquid at common temperatures, but crystallizes at 32° Fahr.; sweet to the taste, and of a penetrating ethereal odor; distinguished from the protiodide by the vapor which it emits on being heated. The periodide of carbon is made by mixing an alcoholic solution of pure potash and of iodine. It forms crystals of a pearly lustre, sweet to the taste, and of a saffron odor. The protiodide is formed by distilling a mixture of the preceding compound with corrosive sublimate. Sweet in taste, and of a penetrating ethereal odor.
Bromide of Magnesium.—Dissolve magnesia in hydrobromic acid. It will crystallize in small acicular crystals, of a sharp taste, very deliquescent and soluble.
Bromide of Sulphur.—Pour bromine on sublimed sulphur. There is formed an oily liquid of a reddish tint.
Bromide of Phosphorus, is formed by bringing phosphorus and bromine into contact in a jar filled with carbonic acid gas. Vaporizes by heat, and is decomposed by water.
Bromide of Silicon, is prepared by burning silicon in the vapor of bromine. A very dense, colorless liquid, emitting dense fumes. We have used this article as an accelerator, and it produces a beautiful but singular picture. It works quick, but possesses no particular advantage.
Bromide of Zinc.—Prepared by digesting a solution of bromine with zinc filings. The iodide is formed in a similar manner. No interest.
Hydrobromic Acid.—Mix the vapor of bromine with about an equal bulk of hydrogen gas, and introduce a coil of red-hot platinum wire. Red-hot iron answers equally well. The combination takes place slowly without explosion. Or, it may be formed by placing a small piece of phosphorus in a glass tube filled with water, and dropping it upon a little bromine. The hydrobromic acid passes over in the form of a gas, and may be passed through water, which will absorb it. Hydriodic Acid is formed in the same way, using iodine in place of the bromine. Hydrobromic acid is decomposed instantly by chlorine and nitric acid.