NIG 



NIC 



finishing the work, which, upon his 

 death, was committed for that purpose 

 to M. de Roberval, professor royal of 

 mathematics at Paris. A "Letter" of 

 Father Niceron's is inserted in the third 

 volume of Liceto's " De quaesitis per Epis- 

 tolas." 



NICHE, in architecture, a concave re- 

 cess in a wall having a semi-circular or 

 elliptical head, intended to contain a sta- 

 tue or bust. 



NICKEL. A white metal, which, when 

 obtained pure, is both ductile and malle- 

 able. It may be forged into very thin 

 plates, their thickness not being greater 

 than 0.01 of an inch. Its colour is inter- 

 mediate between that of silver and tin, and 

 is not altered by the air. It is nearly as 

 hard as iron. Its specific gravity is 8.279, 

 and when forged 8.666. 



The species of nickel ores are, its alloy 

 with arsenic, and a little sulphur and its 

 oxide. 



The first is the most abundant, and the 

 one from which nickel is usually extract- 

 ed. It is known to mineralogists by the 

 name of kupfer-nickel, or copper-nickel, 

 from its colour and appearance. It oc- 

 curs generally massive and disseminated; 

 its colour is copper-red of various shades; 

 its lustre i& weakly, shining, and metal- 

 lic ; it is perfectly opaque ; its fracture is 

 uneven ; it is hard, has no malleability, 

 but is not easily broken ; its specific gra- 

 vity is from 6.6 to 7.5. Urged by the 

 flame of the blow-pipe, it gives vapours 

 with a strong arsenical odour, and melts 

 with difficulty. It dissolves in acids, giv- 

 ing a green solution. Bergman found it 

 to be composed of nickel, iron, cobalt, 

 arsenic, and sulphur. Vauquelin regards 

 it as essentially an alloy of nickel and ar- 

 senic, the iron, cobalt, and sulphur, be- 

 ing accidental. 



The other species, the oxide of nickel, 

 occurs generally as an incrustation, some- 

 times also disseminated, of a friable tex- 

 ture and earthy appearance ; of an apple 

 green colour, without lustre. It is not air 

 tered by the heat of the blow-pipe ; but 

 when mixed with borax gives to it a yel- 

 lowish red colour. Its solution in acids 

 is of a green colour. It occurs generally 

 with kupfer-nickel, or with certain cobalt 

 ores. It is also contained in small quanti- 

 ties in a fossil of the siliceous genus, chry- 

 soprase, to which it communicates an ap- 

 ple-green colour. 



Nickel is extracted from the kupfer- 

 nickel, but it is extremely difficult to free 

 it entirely from the metals with which it 

 is associated. The process given by Che- 



nevix is the most simple. The metal ob 

 tained from kupfer-nickel, by roasting 

 and fusion with three times its own 

 weight of black flux, is dissolved in nitric 

 acid, the solution being boiled, so that 

 the arsenic present receiving oxygen 

 from the acid may be converted into ar- 

 senic acid ; a solution of nitrate of lead is 

 then dropped in, and the liquor evaporat- 

 ed by a very gentle heat, but not quite to 

 dryness. Alcohol poured into this solu- 

 tion precipitates every salt, but the ni- 

 trate of nickel, which has been formed 

 by the double decomposition of the arse- 

 niate of nickel and the nitrate of lead. 

 The alcohol of the solution of nitrate of 

 nickel being evaporated, the metallic salt 

 is redissolved in water and decomposed 

 by potash. The oxide, well washed and 

 dried, is reduced in an Hessian crucible 

 lined with lamp-black. 



By the experiments that have been 

 made on nickel in its pure state, it ap- 

 pears to be proved that it is possessed of 

 magnetic power, and that therefore iron 

 is not the only metal to which it belongs. 

 The magnetic properties of nickel had 

 often been observed ; but as, in the usual 

 processes by which it is obtained, it is al- 

 ways alloyed with iron, it was concluded, 

 with probability, that the magnetism it 

 exhibited was owing to the presence of 

 that metal. Since methods, however, 

 have since been discovered of obtaining 

 nickel in a purer state, the error of this 

 conclusion has been discovered. The ef- 

 fect of the magnet on it is very little in- 

 ferior to that which it exerts on iron ; and 

 the metal itself becomes magnetic itself 

 by friction with a magnet, or even by 

 beating with a hammer. Magnetic nee- 

 dles have even been constructed of it in 

 France, and have been preferred to those 

 of steel, as resisting better the action of 

 the air. The nickel preserves its mag- 

 netic property when alloyed with cop- 

 per, though it is somewhat diminished ; 

 by a small portion of arsenic it is com- 

 pletely destroyed. 



Nickel is extremely fusible ; its fusing 

 point being higher than that of iron. 



This metal is oxyded by exposure to 

 the atmospheric air at a high tempera- 

 ture, though \\fith difficulty. Its oxide is 

 more easily obtained by exposure to heat 

 with nitre; it is of an apple green colour, 

 and is obtained likewise of this colour by 

 precipitation from some of its saline com- 

 binations. It appears to be the oxide at 

 the minimum of oxydement; at least, ac- 

 cording to the experiments of Thenard, 

 another oxide can be formed more high- 



