OF COBALT, &c. 

 S ui. 'Precifilate/ of Nickel* 



A futurated folution of nickel in nitrous acid is 

 well known to he green. All alkalis whatever, 

 cliilblve the combination between nickel and 

 nitrous acid. An hundred weight of nickel pre- 

 cipitated by aerated alkali, is of a very light 

 green colour, which it retains when dry. The 

 powder weighs, when dried, 135 pounds. Caul* 

 lie alkali produce* a funilar precipitate from the 

 fame folution : but 100 pounds of nickel arife 

 only to an hundred and twenty eight, when 

 precipitated from a folution in nitmu acid with 

 cuuilie alkali. JMogillieated alkali produces u 

 powder, of the fame colour nearly, but rather 

 yellower, and liable to a Hume, as it is dried, t 

 greeniih yellow, of a darker hue. The precipi- 

 tate obtained with phlogillicated alkali, after be- 

 ing wrJhed and dried, weighs 250 pounds. 



From acid of nitre in which I had diifolved an 

 hundred weight of common regulu* of nickel, 

 which had pro viouily undergone only a iinglc 

 procefsof reduction, upon the addition of a quan- 

 tity of v.inc, there fublided feventcen pounds of 

 arfenic, in the form of a black metallic powder. 

 Mci.nthne, the mercury flood in the thermome- 

 ter Ut fifteen degrees, Jiy the application of ;i 

 llrong heat the powder was calcined to whitc- 

 nefs. Yet fuch is the mutual attraction between 

 nickel and arfenic, that a conliderable propor- 

 tion 



