frequently used to test the malleability of metals.

A _knife_, for the purpose of ascertaining the hardness of minerals.

The student should also be provided with several three-edged files,
and likewise with some flat ones.

A _microscope_, an instrument with two lenses, or with such a
combination of lenses, that they may be used double or single, is
frequently necessary for the examination of blowpipe experiments, or
the reaction of the fluxes. Common lenses, howsoever cheap they may
be, are certainly not recommended. A microscope with achromatic lenses
can now be purchased so cheap that there is no longer any necessity of
procuring one with the common lens. Besides, there is no reliability
whatever to be placed in the revelations of the common lens; while on
the contrary, the deceptive appearances which minute objects assume
beneath such lenses are more injurious than otherwise. A small cheap
set of magnifying glasses are all that is required for the purpose of
blowpipe analysis, Fig. 12.

[Illustration: Fig. 12.]

A small _magnet_ should be kept on hand, for the purpose of testing
reduced metals.

_Nippers_, for the purpose of breaking off pieces of minerals for
analysis, without injuring the entire piece, are indispensable, Fig
13.

[Illustration: Fig. 13.]