filtrate. By this means organic chlorine compounds, which are not precipitated by solution of AgNO3, are decomposed, the chlorine uniting with the calcium to form CaCl2.

(e) SULPHUR.-Solid compounds may be tested by fusing them with a mixture of pure solid KHO and KNO3. The fused mass when cold is dissolved in water, acidified with HCl and tested in the usual way with solution of BaCl2.

Liquids are gently heated with strong HNO3, or with a mixture of HCl and HClO3, the solution is then diluted and tested with BaCl2.

(ƒ) PHOSPHORUS.-Fuse the substance as in (e) with a mixture of KHO and KNO3, or heat it with strong HNO3. Add water and test as in 98, 2, 5, or 6.

Phosphorus may also be detected by slightly charring the substance and proceeding as in 60.

TABLE K.

146. Separation of Organic Acids.

Remove the metals of the Silver, Copper, and Iron Groups by their respective group reagents. Neutralize the so'ution
with (NH4)HO, add CaCl2, shake well, and allow to stand for at least twenty minutes.

PRECIPITATE.

Oxalic and Tartaric

FILTRATE.

L

to precipitate cold NaHO and filter.

Remaining Acids.

Add to filtrate 3 volumes of strong alcohol and filter.

PRECIPITATE

FILTRATE.

Benzoic Acid, &c.

Citric, Malic and Succinic Acids.

FILTRATE. Wash with alcohol, dissolve in HCl, add (NH4)HO,

4,

boil and filter.

T.
Confirm by
tests 3 &
122,to
ascertain ing again in HCl, and
the pre-
of adding (NH)HO.
Tartaric Confirm by tests 4 and
5, 123, to ascertain
the presence of Ci-
tric Acid,

Confirm by dissolv

sence

Acid.

Acetic and formic acids are tested for in the
original solution. Neutralize (if necessary) with
Na2CO3, boil down to dryness, and test a por-
tion for Acetic Acid by ether test 128, 3.
Or distil with H2SO4 and digest distillate with
excess of PbO to obtain basic acetate of lead.
To another portion of dry residue add dilute
H2SO4 and distil. Heat part of the distillate
with PbO to obtain crystals of lead formiate.
To another part add (NH4)HO till neutral, and
then AgNO3 (test 1, 129), to ascertain the pre-
sence of Formic Acid.

Heat to expel alcohol, neutralize exactly
with HCl, and add Fe2Cl6. Filter.

Wash the precipitate, Formic Acid,
warm with (NH)4HO, &c., &c.
filter, evaporate fil-
trate nearly to dry-
ness. Add HCI to
obtain shining crys-
tals of Benzoic
Acid. Confirm by
test 3, 124.

Uric (137), tannic, and gallic acids are
separately tested. Gallic and tannic are
separated by isinglass, or by dialysis
through a small piece of bladder (143
and 144).

PART V.

REACTIONS OF THE RARE METALS.

147. THE following rare metals are considered here by themselves, and their position in the various groups indicated. For their separation from each other and from the commonly occurring metals, a larger manual must be consulted.

Tungsten, Thallium, Palladium, Rhodium, Osmium, Ruthenium, Gold, Platinum, Iridium, Molybdenum, Selenium,* Tellurium, Uranium, Indium, Beryllium, Zirconium, Cerium, Lanthanum, Didymium, Titanium, Tantallum, Vanadium, Lithium, Cæsium, Rubidium.

* Selenium, although a metalloid, is conveniently included here.

Grouping of the Rare Metals.

148. PRECIPITATED IN SILVER GROUP.

Tungsten (as Tungstic Acid), Thallium (as Chloride).

PRECIPITATED IN COPPER GROUP.

Palladium, Rhodium, Osmium, Ruthenium.

PRECIPITATED IN ARSENIC GROUP.

Gold, Platinum, Iridium, Molybdenum, Tellurium, Selenium.

PRECIPITATED IN IRON GROUP.

Uranium, Indium (Thallium), as sulphides; Beryllium, Zirconium, Cerium, Lanthanum, Didymium, Titanium, Tantalum, as hydrated oxides.

PRECIPITATED AS SULPHIDES ON ADDING HCl TO THE FILTRATE FROM THE IRON GROUP.

Vanadium (Tungsten).

FOUND IN POTASSIUM Group.

Lithium, Cæsium, Rubidium.