(4) in forceps.  On platinum wire fuses and colors the flame
                         violet more or less modified by lime and soda.

  (5) in borax. —­

  (6) in mic. salt. —­

  (7) with carb. soda. —­

  (8) Special reactions.  With bisulphate of potassa in the glass-bulb
                         evolves nitrous fumes.

* * * * *

Mineral.  Polyhalite

Formula. [.K][...S]+[.Mg][...S]+2[.Ca][...S]+2[.H]

Behavior

  (1) in glass-bulb.  Gives off water.

  (2) in open tube. —­

  (3) on charcoal.  Fuses to a reddish bead, which in the reducing
                         flame solidifies and shrinks to a hollow crust.

  (4) in forceps.  On platinum wire fuses and colors the flame
                         yellow from a small quantity of soda.

  (5) in borax.  Dissolves with ebullition to a clear glass,
                         which is slightly colored by iron, and when
                         saturated become opaque on cooling.

  (6) in mic. salt.  As in borax.

(7) with carb. soda.  Fuses.  The alkalies are absorbed by the charcoal
leaving the lime and magnesia infusible on the
surface.

(8) Special reactions.  The alkaline mass when laid on silver gives a
sulphur reaction.

* * * * *

SODA.

* * * * *

Mineral.  Rock-salt

Formula.  NaCl.

Behavior

  (1) in glass-bulb.  Fuses to a clear liquid

  (2) in open tube. —­

  (3) on charcoal.  Fuses, is absorbed by the charcoal and partially
                         volatilized incrusting the charcoal around.

  (4) in forceps.  Fuses with great ease and colors the flame
                         yellow.

  (5) in borax. —­

  (6) in mic. salt. —­

  (7) with carb. soda. —­

  (8) Special reactions.  Gives the chlorine reactions.

* * * * *

Mineral.  Natron

Formula. [.Na][..C] + 10[.H]

Behavior

  (1) in glass-bulb.  Fuses, with the evolution of water.

  (2) in open tube. —­

  (3) on charcoal.  Fuses, and is absorbed into the pores of the
                         charcoal.

  (4) in forceps.  Fuses and behaves as the preceding.

  (5) in borax. —­

  (6) in mic. salt. —­

  (7) with carb. soda. —­

  (8) Special reactions.  Dissolves in acid with violent effervescence.