4258. Acetate of Alumina

4258.    Acetate of Alumina. Add a solution of acetate of baryta to another of sulphate of alumina, and filter. Or, add 5 parts alum to 6 parts sugar of lead, each being first dissolved separately in hot water, and allowed to cool before mixing; decant the clear liquor. The pure acetate is made from pure hydrate of alumina, by digesting it in cold, strong acetic acid, until the latter is saturated. By spontaneous evaporation long transparent crystals form.

4259. Sulphate of Alumina

4259.    Sulphate of Alumina. Saturate dilute sulphuric acid with hydrate of alumina; evaporate and crystallize.

4260. Butyrine

4260.    Butyrine. An oily fluid obtained from butter. Keep clarified butter in a porcelain vessel, at a heat of 66°, for some days; carefully collect the oily portion which separates, and agitate it with an equal weight of absolute alcohol for 24 hours, then pour off the clear and evaporate, treat the oily residuum with a little carbonate of magnesia to remove any free acid, and wash off the butyrate of magnesia thus formed with water; next heat the remaining fatty matter in alcohol, filter, and evaporate, to obtain the butyrine.

4261. Bromine

4261.    Bromine. A dark reddish-colored liquid, having an odor resembling chlorine. It freezes at - 4°,boils at about 135° Fahr., is very soluble in ether, less so in alcohol, and only slightly so in water. "With hydrogen it forms hydrobromic acid, and, with the bases, compounds called bromides or hvdrobro-mates. It is obtained as follows: A current of chlorine is passed through the uncrystallizable residuum of sea-water, called bittern, which then assumes an orange tint, in consequence of bromine being set free from its combinations; sulphuric ether is then agitated with it, and the mixture allowed to stand until the ethereal portion, holding the bromine in solution, floats upon the surface. By decanting, and evaporating the ether, a crude bromine may be obtained at once. To get it pure, the ethereal solution is carefully decanted, and agitated with a solution of potassa, by which means bromide of potassium and bromate of potash are formed. The whole is next evaporated to dryness, and submitted to a dull red heat; the residuum is then powdered, mixed with pure peroxide of manganese, and placed in a retort; sulphuric acid, diluted with half its weight of water, is now poured in. Bed vapors immediately arise, and condense into drops of bromine, and are collected by plunging the neck of the retort to the bottom of a small receiver containing cold water. The bromine forms a stratum beneath the water, and may bo collected and further purified by distillation from dry chloride of calcium. (Cooley.)

4262. Iodide of Cadmium

4262.      Iodide of Cadmium. This is prepared by mixing iodine and cadmium filings in a moist state. This is freely soluble in water or alcohol, and may be crystallized by evaporation from ether solution, in large white transparent crystals. ( U. S. Disp.)