Part 11 (1/2)

LECTURE XXVII

_Of Nickel_

Nickel is a senetical; on which account it is supposed to contain iron, though chemists have not yet been able to separate them

The purest nickel was so infusible as not to run into a e; but then it was in soree malleable

Concentrated acid of vitriol only corrodes nickel Alkalies precipitate it from its solution in the nitrous acid, and dissolve the precipitate

It readily unites with sulphur

Nickel is found either native or mineralized with several other metals, especially with copper, when it is called _kupfer nickel_, or _false copper_, being of a reddish or copper colour

This semi-metal has not yet been applied to any use

_Of arsenic_

What is commonly called _arsenic_ is the calx of a seulus of arsenic_ It is a white and brittle substance, expelled from the ores of several metals by heat It is then refined by a second sublimation, and melted into the masses in which it is cohty tiht of boiling water It acts in many respects like an acid, as it decomposes nitre by distillation, when the nitrous acid flies off, and the _arsenical salt of Macquer_ remains behind

When the calx of arsenic is distilled with sulphur, the vitriolic acid flies off, and a substance of a yellow colour, called _orpiment_, is produced This appears to consist of sulphur and the regulus of arsenic; part of the sulphur receiving pure air froiston; and thus the sulphur becomes converted into vitriolic acid, while the arsenical calx is reduced, and combines with the rest of the sulphur

The coether, is of a red colour, known by the naar_ It is less volatile than orpiment

The solution of fixed alkali dissolves the calx of arsenic, and byalso a disagreeable sulus of arsenic is of a yellow colour, subject to tarnish or grow black, by exposure to the air, very brittle, and of a laminated texture

In close vessels it wholly sublimes, but burns with a small flame in pure air

Vitriolic acid has little action upon this semi-metal, except when hot; but the nitrous acid acts readily upon it, and likewise dissolves the calx, as does boiling h it affects it very little when cold

Most of the isticated marine acid converts the calx of arsenic into _arsenical acid_ by giving it pure air

The acid of arsenic acts more or less upon all metals, but the phenomena do not appear to be of much importance

The calx of acid is used in a variety of the arts, especially in the ments Some atte dangerous, the experiments should be made with caution

_Of Cobalt_