A volatile liquid prepared from alcohol, and containing not less than 92 per cent. by volume of pure ether (C2H5)2O, B.P. A liquid composed of about 74 per cent. of ethyl oxide (C2H5)2O; and about 26 per cent. of alcohol containing a little water. Specific gravity about 0.750 at 15° C. (59° F.), U.S.P.

Characters. - A colourless, very volatile and inflammable liquid, emitting a strong and characteristic odour, and boiling below 105° F. Specific gravity 0.735, B.P.

Reactions. - Fifty measures agitated with an equal volume of water are reduced to 45, by an absorption of 10 per cent. It evaporates without residue.

Preparation. - By distilling rectified spirit with sulphuric acid, and freeing the ether thus obtained from water by redistillation with calcium chloride and lime.

In this process ethylsulphuric or sulphovinic acid and water are first formed, ethyl replacing one atom of hydrogen in the sulphuric acid.

Sulphuric Acid.

Alcohol.

Ethylsulphuric Acid.

Water.

H

SO4 +

C2H5

O =

C2H5

SO4 +

H

O.

H

H

H

H

By the action of fresh alcohol on the ethylsulphuric acid it is decomposed, ether being formed and sulphuric acid being reproduced.

Ethylsulphuric Acid.

Alcohol.

Sulphuric Acid.

Ether.

C2H5

SO4 +

H

O =

H

SO4 +

C2H5

O.

H

C2H5

H

C2H5

Theoretically this process might go on ad infinitum if fresh alcohol were continually supplied; but practically the acid volatilises partly in the form of oil of wine, so that the process cannot go on indefinitely.

Impurities. - Water, alcohol, and fixed impurities.

Tests. - Water is detected by the greater sp. gr., and so is alcohol; the fixed impurities by their remaining on evaporation.

Dose. - 20 to 60 min.

Preparations

B.P.

aether Purus .................................................................

Collodium ...................................................................

6 volumes in 8

nearly.

" Flexile .........................................................

6 „ 8

"

Spiritus aetheris ..........................................................

1 volume in 3

"

" " Compositus ....................................

1 „ 3

"

Tinctura Chloroformi et Morphinae ..........................

1 ,, 32

"

B.P. aether Purus. Pure Ether, - Ether, C4H10O, free from alcohol and water.

K2O, corresponds

to

C2H5

O

or

(C2H5)2O,

ethylic ether.

C2H5

Preparation. - `By washing ether with distilled water, and then distilling from calcium chloride and recently calcined lime. Test. - Specific gravity not exceeding 0.720.

Uses. - Used as an anaesthetic; to prepare some alkaloids, as aconitine; to test the amount of quinine in bark. Ether is sometimes used locally in ringworm, and to dissolve sebaceous matter from the surface of the skin. In conjunction with alcohol it forms a cooling lotion in urticaria and pruritus.

U.S.P. aether Fortior. Stronger Ether, (C2H5)2O; 74.

Preparations. Spiritus aetheris. Spiritus aetheris Compositus.

Characters. - A liquid composed of about 94 per cent. of ethyl oxide and about 6 per cent. of alcohol, containing a little water. Specific gravity not higher than 0.725 at 15° C. (59° F.) or 0.716 at 25° C. (77°F.).

Ether is highly inflammable, and its vapour when mixed with air and ignited explodes violently.

Test. - It should boil actively in a test-tube half filled with it and held a short time in the hand on the addition of small pieces of broken glass.

Uses. - Used for inhalation as an anaesthetic.