^v

MAGN

237

essential volatile oil, and may be given in substance as a stimulantand carminative in doses of gr. x to 9j.

Adulterated with mace from which the oil has been partly extracted.The fraud may be detected by the article being less aromatic, and theblades being more thick and spongy.Madder. See Rubi^: Radix. L.

Magistery of Bismuth, or Spanish White- See Bism. Subnitr. Itis the subnitrate of bismuth, produced by dissolving nitrate of bismuthin a large quantity of water, when it falls down in the form of a whitepowder, which is thus prepared for the cosmetic known by the nameof Pearl powder. Take Jiv of the subnitrate of bismuth, 5y °f fi" cstarch-powder; mix, and put into a glass wide at top and narrow atbottom; pour in Ojss of proof spirit, and after shaking and stirringit, let it stand for two days to settle; then pour off the liquor anddry the powder by evaporation. Repeat this process thrice, andlevigate what remains into an impalpable powder. It will be black-ened by sulphuretted hydrogen, and it is not therefore proper to useit as a cosmetic when going into crowded rooms.Magnesia. L. E. Magnesia tista. D. Calcined Magnesia. Take ^ivof subcarbonate of magnesia, heat it intensely for two hours, or untildilute acetic acid dropped upon it produces no effervescence.

Decomposition. The heat expels both water and carbonic acid, whichusually amount to 50 or 60 per cent, leaving the pure magnesia, anda compound, according to Sir H. Davy, of 40 oxygen, and CO of themetallic base called magnesium.

Adulterated with chalk, gypsum, and flour.

out colour, taste, or smell, and has 2-3 of spec. grav. It ought notto effervesce with acids. Lime may be detected by dissolving it indilute sulphuric acid, and precipitating it with oxalate of ammonia—chalk by dissolving it in nitric acid, and precipitating with subcar-bonate of ammonia. Flour may be detected by its burning whenthrown on red-hot iron or coals.

Insoluble, or nearly so, as it requires 2000 times its weight of water todissolve it.

Medicinalli/, calcined magnesia is an antacid, and when it meets withan acid in the stomach, or bowels, it becomes a neutral salt, and islaxative. In flatulence it is to be preferred to the carbonate. Thedose is gr. x to 5 j in water or milk for cardialgia and acidity. Itmay be combined with supertartrate of potass and manna. It isdouble the strength of the carbonate as an antacid.

Incompatible with metallic and acidulous salts, muriate of ammonia,and acids; but not with lime water.Magnesia Subcarbonas. L.P. Subcarbonate of Magnesia. Carbonas

When genuine it is with-