Magnesia possesses many of the characters of earths and alkaline earths

in common.

DISTINGUISHING TESTS FOR BASES.

FIRST CLASS.

PRECIPITATED BY NH.

White by

White by NH, O. by NH,SH.
Phosphate of Soda and NH,CO2. Soluble
in NH,HCl.

Soluble in NaO and KO. Insoluble in alkal

White by oxalic acid.

Soluble in carbo

Soluble in carbonate

of NH3. Insoluble in NaO.

White by KO SO,, nearly insoluble in HO.
Brownish-red when ignited.

Insoluble in HCl after ignition.

Soluble in alkal-carbonates. Insoluble in NaO. Orange by SH. Chloride decomposed by HO. Blue colour produced by metallic zinc.

3°

Black by NH,SH. Soluble in NaO or KO.
White by SO, Yellow by Chromate of KO.
Brown by NH,SH; dissolved by an excess.
Precipitates Gold Purple.

White by HCl. Black by NH,, NaO, and

SH.

White by NH3.

Black by SnCl.

of NH,SH. Red by KI.

Salts decomposed by HO. Black by NH,SH. Distinguished from PbO by no precipitate with SO3.

Green by NH,. Soluble in KO.

Brownish-black by NH.

Black by NH,SH.

Becomes peroxide by NO.

Yellow by NH, Brown by NH,SH, Insoluble in excess.

Brown, not soluble in NH, and NaO. Yellow, soluble in NH,SH. Brown phosph, of NaO. White then Brown by NH, and NaO. o. by SH. Soluble in salammoniac. Brown by red prussiate. Flesh red by NH,SH.

DISTINGUISHING TESTS FOR BASES.

FIRST CLASS- continued.

PRECIPITATED BY NH..

Brown by NH, and NaO. Yellow by SH. Black
by Zn.

Blue by red prussiate of potash in acid solutions.
Blue by yellow prussiate of potash in acid solutions.
Blue by sulphate of iron. Purple by SnCl.
Yellow by KCl and NH,HCl,

Rose colour by HCl, and evaporation, Black by Zn.
Blue by NH,. A fine blue solution with KÓ,

SECOND CLASS.

NOT PRECIPITATED BY NH3.

Smell of NH, when boiled with NaO.
PtCl Tinges flame Green.

Yellow by

Yellow by PtCl, and on igniting the precipitate
KCl taken up by HO. Tinges flame Violet. Pre-
cipitated by tartaric acid.

O. by PtCl White by antimoniate of potash.
Tinges flame Yellow.

White by phosphate of soda and ammonia. Tinges
flame Purple.

O. by sulphate of lime. White by oxalic acid. Tinges flame Red.

Immediate White precipitate by sulphate of lime. o.
by oxalic acid. Tinges flame Green,

No immediate White precipitate by sulphate of lime,
but after some time. Tinges flame Crimson.
Yellow by SH. Precipitated on copper black by boiling
with HCl. Sol. in NH,SH; Solution precipitated
yellow by HCl. or heat.

DISTINGUISHING TESTS FOR BASES.

OXIDES.

Tellurium,

THIRD CLASS.

PRECIPITATED AND REDISSOLVED BY NH ̧.

White dissolved by NH, and NaO.
by NH,SH.

Brown redissolved

White dissolved by NH, and NaO, and White by NH,SH.
White dissolved by NH,. White and not dissolved by
NaO. Yellow by NH,SH and SH.

Yellow by NH,SH, soluble in excess.
Blueish-green by NH, and dissolved.

Zn precip. Sn.
Yellow-green by

red prussiate. Blueish-green by Na O, from ammoniacal

solutions.

Blue, and dissolved by NHg.
Brown by red prussiate.
Blue, and dissolved by NH.

Blue undissolved by KO.

Blue undissolved by KO

becomes Black on boiling. Brown, by yellow prussiate. Turns a knife dipped into it Yellow.

Brown, and dissolved by NH3. White curdy by HCl, insoluble in NO5. Yellow White by KI.

Flesh Red, dissolved by NH,, Yellow by KO, Yellowishwhite by HgCy precipitate. Sol. in HCl.

CHARACTERS OF GASES.

I. Soluble in water.

1. Chlorine and Chlorohydric acid precipitate AgONO5, White curdy, insol. in NO5.

2. Carbonic acid precipitates lime-water; precipitate redissolved by an
acid with effervescence.

3. Cyanogen, with ABONO5, White curdy, soluble by boiling in NO5.
4. Ammonia. Odor. and precipitates PtCl2, yellow.

5. Protoxide of nitrogen, rekindles a glowing splinter.

6. Sulphurous acid. Smell of burning sulphur. Precipitated by BaCl.
Precip. Sol. in NO5.

7. Sulphohydric acid, or Sulphuretted hydrogen, blackens lead salts. 11. Insoluble in water.

1. Oxygen rekindles a glowing splinter.

2. Hydrogen explodes when mixed with half its bulk of O, and fired.

3. Deutoxide of nitrogen forms orange fumes with oxygen.

4. Nitrogen extinguishes a taper without precipitating lime-water.

5. Carbonic oxide burns with a blue flame.

6. Carburetted hydrogen absorbed by SbCl3.

7. Olefiant gas absorbed by chlorine.

8. Phosphuretted hydrogen takes fire in contact with air.

9. Arsenietted hydrogen burns with a blue flame, depositing metallic

arsenic.

SALT RADICALS.

CHAPTER III.

SUBSTITUTIONAL BODIES, OR SIMPLE SUPPORTERS
OF COMBUSTION.

As chemistry comprehends the study of all the bodies and their compounds, of which the earth is composed, it becomes important, not only to be acquainted with their names, but likewise to have them so arranged in the mind that the student may be able, when a substance is named, to refer it to its proper class. The number of simple substances which have been described amounts to 62, of which, however, several have been very imperfectly examined. These bodies may be divided into two great classes NON-METALLIC and METALLIC. The non-metallic bodies exist in the three states, as gases, liquids, and solids. The elements may also be classed as electro-negative and electro-positive bodies, according to the influence exerted upon them by electricity. They may be also arranged according to their isomorphous properties, or their capacity to replace each other, as follows. 1. Sulphur, Selenium, and Tellurium. 2. Chlorine, Bromine, Iodine, and Fluorine. 3. Phosphorus, Arsenic, Antimony, and perhaps Nitrogen and Bismuth. 4. Carbon, Boron and Silicon. 5. Potassium, Ammonia, Sodium, Silver. 6. Barium, Strontium, Lead. 7. Alumina, Sesquioxides of Iron, Manganese, Chromium, Glucina, Zirconia. 8. Magnesium, Calcium, Protoxides of Manganese, Zinc, Copper, Iron, Nickel, Cobalt, Cadmium, Hydrogen. 9. Titanium, Tin. 10. Molybdenum, Tungsten, Columbium, Pelopium, Niobium. 11. Platinum, Iridium, Osmium. 12. Gold. For practical purposes, however, the divisions previously pointed out will be followed.

The following simple bodies constitute the first class to be considered:

1. The title of these simple bodies indicates that they support combustion by uniting with the combustible substance Thus, when we burn a candle in common air, it is oxygen which combines with the tallow, and contributes to give out light and heat. 2. Again, when a substance containing oxygen, or any of the bodies comprised in this class, is exposed to the action of a galvanic battery, the above elements are attracted by the positive pole, and as positive bodies attract negative, it is obvious that this class must consist of electro-negatives. 3 Those bodies