4168. Solution of Tersulphate of Iron

4168. Solution of Tersulphate of Iron. Take 21/8 troy ounces sulphuric acid, and 13/4 troy ounces nitric acid; mix them with £ pint water in a largo capsule, heat to the boiling point, and add 12 troy ounces sulphate of iron in coarse powder, 3 ounces at a time, stirring after each addition till effervescence ceases. Continue tho heat until the solution acquires a reddish-brown color, and is free from nitrous odor. When, nearly cold add water to make it up to l1/2 pints. (U. S. Ph.)

4169. Ferricyanide of Iron

4169.    Ferricyanide of Iron. This is better known as Turnbull's Prussian blue. (See No. 2674 (Turnbull's Prussian Blue).)

4170. Tannate of Iron

4170.      Tannate of Iron. Dissolve 1 part of tannin in 150 of boiling water; add 9 parts hydrated sesquioxide of iron, freshly precipitated, washed, and dried in tho water-bath; evaporate gently to one half; filter, then add 1 part sugar, evaporate to dryness, and keep in a close vessel. Or: 1 part sesquioxide of iron and 2 of tannic acid evaporated to dryness with 3 parts alcohol.

4171. Nitrate of Iron

4171.    Nitrate of Iron. Tho protoni-trate of iron is obtained by dissolving protosulphuret of iron in dilute nitric acid in the cold, and evaporating the solution in a vacuum. It forms small green crystals, very soluble, and liable to oxidation.

4172. Pernitrate of Iron

4172.     Pernitrate of Iron. A deep red liquid formed by digesting nitric acid diluted with about half its weight of water on the sesquioxide of iron. It is also prepared from the metal. (See No. 116 (Nitrate of Iron).)

4173. Oxide of Manganese

4173.    Oxide of Manganese. There are, according to Cooley, seven distinct compounds of oxygen and manganese, but the only one directly employed in the arts is the black oxide (binoxide or deutoxide) of manganese. It is a very plentiful mineral production, and is found in great abundance in many parts of Europe. The manganese of commerce is prepared by washing, to remove the earthy matter, and grinding in mills. The blackest samples are esteemed the best. It is chiefly used to supply oxygen gas, and in the manufacture of glass and chlorine; in dyeing, and to form the salts of manganese.

4174. Chloride of Nickel

4174.    Chloride of Nickel. Neutralize muriatic acid with oxide (protoxide) of nickel, and evaporate gently; small green crystals of chloride {muriate) of nickel. If these crystals are pure, they are rendered yellow and anhydrous by heat; if cobalt be present the salt retains a green tint.

4175. Protoxide of Nickel

4175.    Protoxide of Nickel. The protoxide (oxide) of nickel is obtained in an anhydrous form by heating oxalate of nickel to redness in an open vessel. The hydrated oxide is an ash-grey powder formed by precipitating the oxalate of nickel with caustic potassa.