M. Descotils has shewn, that when iron and charcoal are strongly ignited with boracic acid, the iron produces, during its solution, boracic acid.

It has therefore been supposed, that iron is capable of combining with boron. With potassium and sodium, iron is susceptible of union, forming alloys more fusible and white than iron.

It may be proper to mention, that the formation of tin plate depends upon the chemical affinity between iron and tin. See Tin.

SECTION XI.

OF NICKEL.

Experiment 1. To obtain nickel, the ore is first roasted, in order to free it from sulphur and arsenic; it then is changed into a greenish oxyd. This oxyd is mixed with two or three parts of black flux. The mixture is put into a crucible, and being covered with decrepitated muriate of soda, it is brought to the state of fusion, by the strongest heat of a smith's forge.

When the crucible is broken, there is found at the bottom, under brown, blackish, and sometimes blue scoriæ, a button of a yellowish white colour, equal in weight to a tenth, a fifth, and even a half of the ore employed. This metal, however, is still far from being pure.

In order to purify it, the button obtained is again broken into small pieces, strongly heated, and then digested with its own weight of concentrated sulphuric acid, and distilled to dryness. The dry mass is dissolved in water and filtered. This solution, in general, deposits crystals of arsenic, and finally affords dark green crystals of sulphate of nickel. This sulphate is re-dissolved in water, and decomposed by carbonate of potash. The precipitate is dissolved in liquid ammonia; the blue solution leaves a residuum

which is filtered off, and the filtered solution saturated with nitric acid. The nickel is then precipitated in the form of a grayish green powder, by carbonate of potash. From this oxyd the metallic nickel is obtainable by exposing it to heat, when made into a mass with oil and a little charcoal powder.

The nickel obtained in this manner was, until lately, considered as perfectly pure. It possesses, however, magnetic properties. It is therefore contaminated with iron.

Chenevix has proposed the following process, in order to obtain this metal in a state of absolute purity:

Experiment 2. Take the native sulphuret of nickel, reduce it to a powder, and roast it in contact with charcoal powder over a gentle fire. When no more fumes arise, then pour nitric acid over it, and dissolve it by heat in a Florence flask. Decant the solution, filter it through bibulous paper, and evaporate it to dryness in a glass basin. Dissolve the nitrate of nickel in a sufficient quantity of distilled water, and decompose it by the addition of the strongest liquid ammonia, taking care to add it in excess. The oxyd of nickel and cobalt will thus be re-dissolved; then let the solution stand undisturbed till a precipitate again ensues. The solution must then be evaporated; it becomes blue during this process, by the precipitation of the cobalt, which should be separated, and the evaporation be then continued to dryness: the residue will be pure oxyd of nickel.

In order to reduce this oxyd to the metallic state, let it be made into a paste with oil, mix it with about three parts of black flux, and put it into a crucible, covering it with borax and muriate of soda, and heat the crucible violently for an hour and a half in a forge; a button will be obtained, which is pure nickel.

Several processes have been recommended to obtain nickel in a state of purity. The substance from which nickel is procured, was first supposed to be an ore of copper. It is found in different parts of Germany, and was called by miners Kufernickel, or "false copper.' It was afterwards investigated by Constedt in 1751, and

It

found to contain a new metal. Nickel is of a white colour, resembling silver. Its specific gravity rather exceeds 8.00. It is malleable both cold and hot. is attracted by the magnet, and, like that metal, may be converted into a magnet. It is fusible at 160° Wedgwood. Nickel on exposure to heat is soon tarnished, and, if in powder, it is converted into oxyd. If the oxyd be exposed to a strong heat, it is reduced to a metallic state. There are two oxyds of this metal, the green and the black, the former is the protoxyd and the latter the per-oxyd. If the solution of nickel in nitric acid be decomposed by carbonate of potash, and the precipitate exposed to a faint red heat, the prot-oxyd of nickel will be formed.

This oxyd contains about 22 per cent. of oxygen, is soluble in ammonia, and forms with it a blue solution. The per oxyd of nickel is formed by causing a current of oxymuriatic acid to pass through water holding prot-oxyd of nickel suspended in it; a portion is dissolved, and the rest acquires a black colour. oxyd is likewise soluble in ammonia.

The

Sulphur combines with nickel by fusion, and forms a bright gray sulphuret. According to Mr. E. Davy, that besides this sulphuret, which contains about 34 per cent. of sulphur, there is a super-sulphuret, which may be formed by heating the gray oxyd with sulphur, and which contains about 56.5 of nickel to 43.5 of sulphur.

Phosphorus and nickel unites into a phosphuret, which may be formed either by fusing nickel along with phosphoric glass, or by dropping phosphorus into it while red hot. The alloys, which this metal forms, are imperfectly known. In all the meteoric stones. that have been examined, it is remarkable that the iron is alloyed, by from 1.5 to 1.7 per cent. of nickel. The alloy of iron and nickel is much less liable to rust than common iron. The oxyd of nickel will im part colours to enamels and porcelain.

SECTION XII.

OF NICOLANUM.

Dr. J. B. Richter has announced the existence of a new metal, to which he has given the name of nicolanum, because it always accompanies nickel in the ores of that metal. This metal has not hitherto been examined, nor recognized by other chemists. Its existence, however, is rather doubtful. Dr. Richter ob serves, that he was surprised to find, that nickel, after being purified from cobalt, iron, and arsenic, and after that reduced without the addition of a combustible body, never formed a mass, but was always found dispersed in small particles in a hard heavy substance, which had the appearance of the remains of vitrified copper.

The following additional remarks, are taken chiefly from the Annales de Chimie, Ixiv. and Nicholson's Journal, No. 48, p. 261.

It resembles cobalt

1. By its property of super-saturating itself with oxygen, at the expense of the nitric acid, and thus forming a body which resembles the black oxyd of manganese with regard to its solubility in the acids: 2. By its property of not being reducible but by the intervention of a combustible body.

It differs from cobalt

1. By the blackish-green colour of its solution, even when they are entirely neutralized. It is known that the neutral solutions of cobalt in the sulphuric, nitric, and muriatic acids, are of a crimson-red colour; and that the muriate of cobalt alone becomes of a greenish-blue on being deprived of its water: from whence it happens that an excess of acid produces this colour, because it combines with the water. With the muriate of nicolanum precisely the reverse takes place; when mixed with water it is green (although of a less beau

tiful colour than the cobalt without water) and when deprived of its water it becomes reddish. 2. By the colour of its carbonate: that of cobalt is of a beautiful poppy blue, but the carbonate of nicolanum is a bluish green inclining to a pale gray. 3 By the colour of its oxyd precipitated without carbonic acid: that of cobalt is of a deep blue, and changes on washing to a blackish brown; but this oxyd of nicolanum is of a greenish blue, and its colour does not change. Nicolanum resembles nickel

1. By its strong magnetic quality; although this is not so great as that of nickel. 2. By its malleability, which however is less than that of nickel. 2. By the deep green of its solutions; although this colour is not so beautiful as that of the solutions of nickel.4. By the loss of this green colour when its neutral combinations are deprived of water. 5. By the colour of the acid solution with an excess of ammonia, which cannot be well perceived by candle-light.

Nicolanum differs very distinctly from nickel

1. Because it cannot be reduced without a combustible body added to it. 2. Because nitric acid attacks and oxydates it more easily. Nickel is not near so readily acted on by the nitric acid if it is not mixed with the nicolanum, which almost always happens with the magnetic nickel which is considered to be in a state of purity, and which has not been reduced per se before the discovery. 3. It also differs from nickel by the property first mentioned of those in which it resembles cobalt 4. By the colour of its combinations with the acids, when deprived of water: this colour in nickel is almost a buff (chamois) and in nicolanum a reddish, except in the nitrate of nicolanum, which cannot be deprived of water without decomposing it. 5. By the colour of precipitates, mentioned in the second and third articles concerning the properties wherein this new metal differs from cobalt, which are in those of nickel of a green colour, entirely different from those of nicolanum, which latter are of a much more agreeable green, especially those of the carbo nate.