If cane sugar or dextrine is found, it is boiled for 1/2 hour with acidified water to convert these substances into glucose. If none of these impurities is present, the amount of water is found by Vogel's well-known method.

Dr. Odling mentions the curious fact that hydrocyanic (prussic) acid is an excellent test for the purity of glycerine, the slightest admixture of any foreign substance causing the glycerine to turn yellow in a short time if a little hydrocyanic acid be stirred into the liquid.

According to klever, 100 parts glycerine will dissolve

Parts.

Acid arsenious....

20.00

,, arsenic....

20.00

„ benzoic ..

10 to 20.00

,, boracic.....

..10.00

Parts.

Acid oxalic.......

. 15.00

,, tannic • • • •

. 50.00

Alum...

. 40.00

Ammoniy carbonate...

,. 20.00

,, muriate.....

. 20.00

,, Antimony tratrate....

. 5.50

Atropine.......

.. 3.00

,, sulphate..

.. 33.00

Barium chloride...

. 10.00

Borax...

. 60.00

Brucine....

. 2.25

Cinchona....

. 0.50

,, sulphate....

. 6.70

Copper acetate......

. 10 00

„ sulphate........

. 3000

Iron lactate....

. 16.00

,, sulphate...

25.00

Iodine....

1.90

Lead acetate....

. 20.00

Mercury bichloride....

7.50

,, bicyanide.....

27.00

,, arseniate....

. 50.00

Potash chlorate...

8.00

„ and iron tartrate ..

. 8.00

Potassium bromide...

. 25.00

,, cyanide...

. 32.00

,, iodine..........

. 40.00

Morphine....

. 0.45

,, acetate........

. 20.00

,, murite...

. 20.00

Soda arseniate .......

. 50.00

„ bicarbonate ......

. 8.00

,, carbonate...

98.00

Phosphorous....

0.20

Sulphur.....

. 0.10

Strychine....

4.00

,,nitrate....

. 0.25

,, sulphate....

. 22.40

Veratrine......

1.00

Zinc chloride....

. 50.00

,, iodine...

. 40.00

,, sulphate............

..35.00

Glycerine is particularly valuable as a solvent for gum-arabic, as also in paste. Glue, by continued digestion, is soluble in glycerine, gelatinising on cooling. Glycerine dissolves aniline violet, alizarine, and alcoholic madder extract. A solution of aniline colour in glycerine is often used for stamping with rubber hand stamps. Glycerine is employed to extract the perfume from flowers, and the aromatic principle of red peppers.

Sulphate of quinine dissolves in 10 parts glycerine when hot, but when cold separates in clots, which, when triturated with the supernatant liquid, gives it the consistence of a cerate, very useful for frictions and embrocations. Warm glycerine (50 parts) will hold in solution when cold 1 of salicylic acid; 300 parts water may be added without causing precipitation.

Glycerine is daily becoming of greater importance to the textile manufacturer. As a lubricant of machinery it is invaluable, and in many instances preferable to oil or greases, especially where such machinery is exposed to the action of the air or great alterations of temperature; it neither thickens, freezes, nor gets rancid, thus keeping the rubbing parts constantly lubricated, which cannot be done by substances which desiccate, and retain the dust flying about in the air, thus clogging the bearings. For lubricating purposes, the pure glycerine may be mixed with half its quantity of olive oil. Glycerine does not attack metals like many oils which have been treated with acids.

Glycerine is not of inferior importance in weaving; by its use the size will never tend to smell badly, and a hand-loom weaver may work at all times, either with an open window or with a large fire in his room; his yarn will always be in a good condition, and not become brittle, nor will cloth sized .with a compound containing glycerine ever mildew or rot; and the following mixture is therefore recommended for this size, viz., 10 lb. farina, 24 lb. glycerine of 28° B., 2 lb. sulphate of alumina, and 6 qt. water.

Glycerine is not only a good solvent for aniline colours, but it tends likewise to preserve for a long time the compositions of albumen, of casein, and solutions of gum used in finishing; it keeps them in a liquid state, and prevents them from putrefying through its antiseptic qualities.

It is also of great use for printing woollen or worsted goods, because the colours printed with it are thus, before the steaming, kept in a humid state,while in cotton printing it accelerates and favours the oxidization of the mordants before the dyeing. In genera), for finishing colours and mordants, 8 oz. suffice lor 1 gal. For dyeing, printing, and finishing, it is not necessary that the glycerine be perfectly white, for when of a pale yellow it will give the same results, while its price will be much lower. Only for very delicate colours, such as ultramarine and others, it is advisable to take purified glycerine. Glycerine of 26° to 28° B. suffices, when exempt from acid or alkali - i.e. when it turns litmus paper neither red nor blue; glycerine of 3o° is seldom used. It must not contain any lime, if it is to be used for colours. To test it for this, a little of the suspected glycerine should be poured into a test-tube, then mixed with half its quantity of water, and a few drops of a solution of oxalic acid is added.

If the solution contains lime, it is clearly shown by the white precipitate which will deposit after a little rest.

Glycerine is sometimes adulterated with grape sugar, common syrup, or similar substances, especially when it has not been purified, and is still of a brownish colour; it loses in such a case a good deal of its aroma, but retains its moderate degree of fluidity, and the buyer is easily deceived.

In Dresden, glycerine is generally used in place of water in gas-meters; after it has been so used for some vears it becomes foul and requires purification. The fluid is first heated for 12 hours to 122° to 146° F. (50° to 60° C), and next to 266° to 302° F. (130°; to 150° C), in order to eliminate water, ammoniacal compounds, and other volatile impurities; the glycerine is next filtered over granulated animal charcoal. Some 300 to 400 cwt. of glycerine are aunually purified in this manner at Dresden. It is said that the cloudiness produced on glass by water in a vaporous state (dew, breath, steam), may be prevented by wiping the surface with a rag moistened with glycerine. Glycerine coloured with aniline has been used in barometer tubes at Kew.