NICKEL ORES. 265 



process, proposed by Wohler : 1 part of the ore is fused with 3 of 

 pearlash and 3 of sulphur. The arsenic forms a soluble compound 

 with the sulphur and potash, and the nickel an insoluble sulphuret. 

 This is well washed with water and dissolved in nitric acid ; and the 

 solution, after any lead, copper, or bismuth, that may be present, have 

 been precipitated by a current of sulphuretted hydrogen, is precipitated 

 by caustic or carbonated potash or soda. The washed precipitate i 

 now acted on by an excess of oxalic acid, which forms with the peroxyd 

 of iron, that is generally present, a soluble, and with the oxyd of nickel 

 an insoluble, oxalate, which of course includes any cobalt that the ore 

 may have contained. The oxalate is now dissolved in an excess of am- 

 monia, and the solution exposed to the air. As the ammonia escapes, 

 the nickel is deposited as an insoluble double oxalate, while the cobalt 

 remains dissolved as a soluble double oxalate of the metallic oxyd with 

 ammonia. The nickel salt, being ignited, leaves an oxyd which may 

 be reduced by heating with charcoal ; or it may be dissolved in acid and 

 again converted into oxalate, which this time is free from cobalt and 

 appears as an apple-green powder. The oxalate of nickel, being well 

 washed, dried and ignited in a closed crucible, with an aperture for the 

 escape of gas, leaves metallic nickel, which, if the heat be very intense, 

 is fused to a button. Its color is between that of silver and tin. 



As nickel does not rust or oxydize, (except when heated,) it is supe- 

 rior to steel, for the manufacture of many philosophical instruments. 



An alloy of copper, nickel, and zinc, has been much used for various 

 purposes, under the name of German silver, or argentane. Good Ger- 

 man silver consists of copper 8 parts, nickel 3, zinc 3^. An inferior 

 article is made of copper 8, nickel 2, zinc 3£. Below the proportion 

 of nickel last stated, the alloy approaches pale brass and tarnishes 

 readily, while the better kind has the appearance of silver, and retains 

 well its polish. It is, however, easily distinguished from silver by a 

 somewhat greasy feel. 



But " German silver" is not a very recent discovery. In the reign 

 of William III, an act was passed making it felony to blanch copper in 

 imitation of silver, or mix it with silver for sale. " White copper" has 

 long been used in Saxony for various small articles ; the alloy employed 

 is stated to consist of copper 88*00, nickel 8" 75, sulphur with a little 

 antimony 0*75, silex, clay and iron, 1-75. A similar alloy is well known 

 in China, and is smuggled into various parts of the East Indies, where 

 it is called packfong. It has been sometimes identified with iht 

 Chinese tutenague. M. Meurer analyzed the white copper of China, 

 and found it to consist of copper 6524, zinc 1952, nickel 13, silver 25 r 

 with a trace of cobalt and iron. Dr. Fyfe obtained copper 404, nickel 

 316, zinc 25.4, and iron 26. It has the color of silver, and is -emark- 

 ably sonorous. It is worth in China about one^fourth its weight of sil 

 ver, and is not allowed'to be carried out of the empire. 



Nickel alloyed with iron, as in meteoric iron, renders it less liable, to 

 rust ; but with steel the tendency to rust is increased. 



Arncles are now plated with nickel, by galvanic precipitation from 

 the sulphate. 



How is nickel obtained from the ore 1 For what is nickel used 1 

 What is German silver ] Wha is the Chinese packfong 1 



