154,

FERR

cured by digesting pure Prussian blue in potass till the alkali isneutralized, when the peroxide of iron being set free, a yellow liquidis formed, which yields crystals of ferro-cyanate of potass by evapora-tion. It is made also on a large scale by igniting hoofs, horns, &c.with potass and iron. It is an excellent test for iron.Soluble in less than its own weight of water." Ferro-cyanic Acid is procured in crystals by dissolving 58 grains ofcrystallized tartaric acid in alcohol, and mixing the liquid with 50grains of the ferro-cyanate of potass, dissolved in the smallest possi-ble quantity of hot water, when the bitartrate of potass is pre-cipitated, and the clear solution upon being evaporated, deposits theacid in small yellow cubic crystals. It has no smell, is not volatile,and in small quantities is not poisonous. M. Porrett calls itFerruretted Chyazic Acid.Test. Any of the per-salts of iron, when no free alkali is present, furnisha very delicate test of this acid, by forming with it Prussian blue.Ferrum. L. E. D. P. Iron, or Iron Filings. Ramenla vel Scobs. Itis necessary to be careful to have the filings of soft iron, and notintermixed with steel. They are tonic and stimulant if taken insubstance, and when they meet with an acid in the stomach orbowels, otherwise they are probably inert. It is better therefore toprescribe some o£ the other preparations of iron. Dose gr. v to 3j ofthe filings in form of pill or electuary. At present they are chieflyused for making other chalybeate preparations.Eiders into Ferri Limatura Purif. E. Ferri Acet. D. Ferri Carbon.E. D. Ferri Sulph. L. E. D. Ferrum Tartarizat. L. FerriOxydum Rubrum. D. Ferri Oxyd. Nigrum. E. D. Ferrum Ru-brum. D. Liq. Ferri Alkalini. L. Tinct. Acet. Ferri. D. Vin.Ferri. L. D.Ferrum Ammoniatum. L. Ammoniated Iron, or Martial Flowers.Ferrum ammoniacale. O. Murias ammonias el Jerri. E. D. P. Takeftj each of subcarbonate of iron, muriatic acid, and muriate ofammonia, pour the acid upon the subcarbonate, and let it stand tillthe effervescence ceases, filter through paper, and evaporate to dry-ness, mix the residuum with the muriate of ammonia, sublime themimmediately by a strong fire, and powder the sublimate. It is of ayellow orange colour, and has a styptic taste.Decomposition. The subcarbonate of iron decomposes the muriate ofammonia by means of the heat, the carbonic acid partly passes ofF,and partly unites with the ammonia, while the portion disengagedof the muriatic acid unites with the iron, and there remains a mix-ture of submuriate of iron, submuriate of ammonia, and subcarbonateof ammonia.