Sesquioxide of Iron

Should hydi osulphooyanio acid be present in hydrocyanic acid, it may immediately be discovered, by adding a salt of sesquioxide of iron, when a fine blood-ted color, more or less deep, appears. 

Dr. Bostock s summary is as follows In order to procure an ink which may he little disposed either to mould or to deposit its contents, and which, at the same time, may possess a.deep.black hue not liable to fade, the gells should be macerated for some hours in hot water, and the fluid, filtered tire filtrate should, be then exposed for about fourteen, days to a warm atmosphere, when any fungoid growth that may be observed must, be removed. A solution of sulphate of iron is to be. employed which has been boiled, or. exposed for some time, to the air, and in which there is consequently an admixture of sesquioxide of iron.. If the infusion of galls be made considerably stronger than is generally directed, the ink formed in this manner will not necessarily require the addition of a mucilaginous substance to render it of a proper consistence. 

Seatpiichloride—Fea Cl,—is formed by the combustion of iron wire in dry chlorine gas, or by transmitting that gas over iron moderately heated, when it is obtained in small iridescent plates of a red color, which deliquesce readily, and dissolve in water, alcohol, and ether. The readiest mode of obtaining it in solution, is to dissolve sesquioxide of iron in hydro-chlorio acid. 

Prussian blue is regarded as a compound of three equivalents of ferroeyanogen with two of iron, and its composition is therefore expressed by the formula 8 Cfy -j- 2 Fea, or Fe, Cys, It is formed whenever a salt of sesquioxide of iron is added to a soluble metallio ferrocyanide. The usual method is to precipitate a solution of sesquiehloride or sesquinitrate of iron by ferrocyanide of potassium and In point qf fact a very important part of its manufacture consists in the preparation of this latter salt, which will now be described. 

Ferridcyanide of Potassium, or Red prussiate of potassa, is formed by passing a current of chlorine through a solution of the yellow prussiate, until a portion of the liquor, taken for trial, is found to give no precipitate with a salt of sesquioxide of iron. The solution is... 

With sesquioxide of iron, the red prussiate gives no precipitate the yellow prussiate, a dark-blue precipitate, which Is prussian bbte—... 

It is stated that protoxide of mercury ia occasionally adulterated -with minium or red lead, sesquioxide of iron, and powdered brick. Such substances are readily detected by heating the substance to a dull heat the protoxide of meroury sublimes, and leaves the nonvolatile matters in the crucible, or the mercurial compound maybe treated with dilute nitric add, to dissolve the mercurial oxide and should minium be present, a pace-colored binoxide of lead remains together with the other adulterants, if any be present. On adding dilute sulphuric acid to the door liquor obtained in the foregoing, a white precipitate of sulphate of lead falls, corroborative of the existence of a lead compound. 

Meconate of sesquioxide of iron is a very Solable Balt, of a blood-red color, which is decolorised by snipburous acid and protochloride of tin. 

Estimation.—Phosphorus is quantitatively determined as pyrophosphate of magnesia—2 Mg 0, POj—or as basio phosphate of sesquioxide of iron, being first converted into phosphoric acid by the action of boiling diluted nitric acid. 

The rosidual mass left after burning, and -which consists principally of sesquioxide of iron mixed with more or less protosulphide, was at one time rather an annoyance than of any value to the manufacturer but at the present time many of them have erected furnaces for. the express purpose of extracting the small per centage of copper which it contains. 

Potasso-tartrate of Iron—KO, e, Oj, C, H4 0 —is an important medicinal salt.. It is obtained by digesting the hydrated sesquioxide of iron with water, and bitartrate of potassa at. 125° for twenty-four to thirty-six hours, and evaporating the residue on plates. In lustroue scales of dark brown -color. 

Very frequently the siliented oxide of zino and the carbonate are confounded under. the title calamine. Two principal classes of calamine are recognized, namely, ordiimiy white calamine, which may be a carbonate or a silicate of the oxide, containing but a very small proportion of ferruginous matters, and the red, which differs from the foregoing, but only by ita containing more hydrated sesquioxide of iron or its salts,... 

Sesquioxide of Iron—Fe 0.—This is prepared by the calcination of green vitriol, upon the purity of which the brilliancy of the color in a great measure depends, For the calcination a thick cast-iron vessel or earthenware retort is required. During the operation the 5... 

Ferric citrate 4160 Fe2(C6Hj07)2 Citrate of iron citrate of sesquioxide of Iron prussiate of Iron. 

Tannate of on. Dissolve 1 part of tannin in 150 of boiling water add 9 porta hydrated sesquioxide of iron, freshly precipitated, washed, and dried In the water-... 

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