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colour, does not crystallize, and when evaporated to dryness soon attracts moisture and becomes again liquid. As it is formed with the per oxyd, the intention in using nitric acid in the former experiment, is to furnish oxygen to the metal, by which the maximum of oxydizement is obtained ; at the same time nitric oxyd is disengaged.


Experiment 1. If iron be dissolved in sulphurous acid ; the solution, or evaporation, will yield crystals of sulphite of iron.


Experiment 1. If equal parts of phosphate of soda, and sulphate of iron, be mixed together in solution, a blue precipitate will be formed, called phosphate of iron.

Rationale. The sulphuric acid of the sulphate passes to the soda, and the phosphoric acid of the phosphate, unites with the iron into a phosphate of iron.

Remark. In this state, phosphate of iron is a tasteless powder, insoluble in water, but soluble in nitric acid. It occurs native, crystallized in blue coloured prisms.

Experiment 2. If oxy-sulphate of iron be decomposed by phosphate of soda, a white powder is obtained, called oxy-phosphate of iron.

Rationale. The per-oxyd of iron unites with the phosphoric acid, while the sulphuric acid combines with the soda, forming sulphate of soda.

Experiment 3. If a solution of potash be poured on oxy-phosphate of iron, it will be converted into sub-oxyphosphate, which is of a brown colour.

Rationale. The alkali unites with a part of the phosa phoric acid, and of course converts the oxy-phosphate into sub-oxyphosphate of irop.

Remark. The sub-oxyphosphate is an insoluble pow

der; but soluble in the serum of blood, and is suppos by some to give the red colour to the blood.



Experiment 1. If sulphate of iron be precipitateci an alkaline carbonate, a powder will be obtained, calle carbonate of iron.

Rationale. The sulphuric acid unites with the kali, and the carbonic acid combined with the oxy iron, forming carbonate of iron.

Remark. Carbonate of iron has been found nati: crystallized in rhombs. Rust is frequently a carbork of iron. Hence some of the colleges for the preparation of rust of iron, the precips tion of iron in the manner before mentioned. The a bonate contains 59.5 prot oxyd of iron, 36 acid, as water. When iron is dissolved in water impregos with carbonic acid, the artificial ærated chalybeate is formed. It is this compound which is often fas in those waters called chalybeate, of which the lic States abound. Waters of this description, bestir having a ferruginous taste, and occasioning a black dark brown precipitate with tincture of galls, proday on boiling, a brown coloured precipitate, or ochre. " the iron be held insolution by a fixed acid, as the so phuric, it does not precipitate on boiling, and the use re-agents give the same phenomena before as wellafter boiling


Experiment 1. If iron filings be introduced ir? fluoric acid, they will be dissolved and form Aluate iron.


Experiment 1. When sulphate of iron in solution 3

he smided to sub-borate of soda, also held in solution, a
ered whecipitate will be formed, which is borate of iron.

Rationale. The sulphuric acid unites with the soda,
d the boracic acid with the iron.

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a portes Experimens 1. If sulphuret of iron be dissolved in

stic acid, and the solution filtered and evaporated, mharic xitstals of acetate of iron, in the form of prisms, will acid cons produced.

of ince Experiment 2. If per-oxyd of iron be dissolved in
of in hetic acid, the result is a salt, called oxacetate of iron,
Pussequor much in use by calico-printers.
of the Experiment 3. If iron be dissolved in pyroligneous
before formed called iron liquor by the calico-printers,

Tokat of pst, obtained by the distillation of wood, a fluid will
Corrdo dich is similar to acetate of iron.

solved in a


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sbeate, or experiment 1. If succinate of ammonia be added to this sphate of iron, a brown precipitate will be produced, and occasi uccinate of iron. See Succinate of Ammonia.

tincture and precipita

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Experiment 1. If iron be dissolved in benzoic acid,
result is benzoate of iron, which, on evaporation will
n yellow crystals, soluble in water and in alcohol,



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experiment 1. If oxalic acid be added to the prot
'per-oxyd of iron, a solution will take place, and pro-
e oxalate of iron : with the former oxyd the simple
wate is formed, but with the latter, the oxy-oxalate.

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Experiment 1. When prot oxyd of iron is dissolved in tartaric acid, the result is tartrate of iron, which crystallizes, and is sparingly soluble in water; but,

Experiment 2. When the per-oxyd of iron is dissolved in the same acid, the oxy-tartrate is formed, which is red and does not crystallize.


Experiment 1. If iron be dissolved in citric acid, citrate of iron will be produced, which deposits small crystals very soluble in water.


Experiment 1. Malic acid when combined with iron, forms malate of iron, which is a brown solution not crystallizable.


Experiment 1. When tincture or infusion of galls is added to a solution of iron, a deep blue or black powder called gallate of iron is produced.

Remark. It has been asserted, that although this compound is formed in the making of black ink, black dye, the colouring of tanned leather, &c., yet it consists for the most part of another principle, called tannin, combined with the same metal. See iron.


Experiment 1. If iron filings be digested in a solution of sulphate of iron, in order to form a sulphate with a minimum of oxygen in the oxyd, and added to prus,

siate of potash, a white precipitate will be formed called prussiate of iron; but,

Experiment 2. If the common sulphate of iron be used, or in preference the oxysulphate, the precipitate will be of a deep blue colour, forming the oxy-prussiate of iron, analogous to prussian blue. See Iron.


Experiment 1. If arseniate of potash be added to sulphate of iron, in which the iron is at the minimum of oxydizement, a green powder will be formed, called arseniate of iron ; but,

Experiment 2. If the same salt be added to oxysulphate of iron, a brownish red powder will be formed, called oxarseniate of ir See enic.

Remark. The other salts of iron are not much known.

The salts of iron form a green, yellowish, or reddish solution, and are known by the following characters:

1. Prussiate of potashi precipitates a powder either blue, or becomes so when exposed to the air.

2. Hydro-sulphuret of potash occasions a black precipitate.

3. Gallic acid, or infusion of nut-galls, throws down a black or purple precipitate.




Experiment 1. If very diluted nitric acid be poured on tin, the metal will be dissolved, and form a yellow coloured solution, of nitrate of tin. Remark. This salt contains the deut-oxyd of tin.


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