(4) in forceps. —­

  (5) in borax.  Behaves as magnesia.  Sometimes a slight
                         iron-reaction.

  (6) in mic. salt.  As in borax.

  (7) with carb. soda.  Fuses to a bead, the soda is then absorbed,
                         leaving an infusable mass of magnesia.

  (8) Special reactions.  The magnesian residue obtained by fusing with
                         carbonate of soda gives the magnesian-reaction
                         with nitrate of cobalt.  Dissolves with
                         effervescence in warm HCl.

* * * * *

Mineral.  Mesitine spar

Formula. ([.Mg][.Fe][.Mn])[..C].

Behavior

  (1) in glass-bulb.  As magnesite.

  (2) in open tube. —­

  (3) on charcoal.  Is infusible.  Assumes a deep brown color.

  (4) in forceps.  V.

  (5) in borax.  Gives the iron and manganese-reaction.

  (6) in mic. salt.  As in borax.

(7) with carb. soda.  As magnesite, but the residual mass has a dark
color from iron and manganese.

(8) Special reactions.  Dissolves with effervescense in warm HCl.  With
carbonate of soda and nitre gives a
manganese-reaction.

* * * * *

ALUMINA.

* * * * *

Mineral.  Sapphire
                         Corundum
                         Emery

Formula. [...Al=].

Behavior

  (1) in glass-bulb. —­

  (2) in open tube. —­

  (3) on charcoal. —­

  (4) in forceps.  V.

  (5) in borax.  In fine powder dissolves slowly to a colorless
                         glass.

  (6) in mic. salt.  As in borax.

  (7) with carb. soda. —­

  (8) Special reactions.  In fine powder moistened with cobalt-solution
                         and heated yields a blue color.

* * * * *

Mineral.  Websterite

Formula. [...Al][...S] + 9[.H].

Behavior

  (1) in glass-bulb.  Gives off water, and, when heated to incipient
                         redness, sulphurous acid.

  (2) in open tube. —­

  (3) on charcoal.  Gives off water and SO^{3}, leaving an infusible
                         mass.

  (4) in forceps.  V.

  (5) in borax.  Behaves as alumina.

  (6) in mic. salt.  As in borax.

  (7) with carb. soda.  Yields an infusible mass, which laid on silver
                         and moistened, produces a black stain.