Eaux, of the liqueuriste, are aromatised spirits or cordials.

EB′LANINE. The yellowish-red, crystallisable, solid substance, which is left behind in the retort, when wood spirit is rectified from quicklime. It is insoluble in water, and sublimes without fusion at 273° Fahr.

EBONITE. The only difference between this and vulcanite, consists in the colouring materials used. See Caoutchouc.

EB′ONY. The wood of the Diospyrus Melanoxylon, an East Indian tree, of the natural order Ebenaceæ. Two other species of the same genus, namely, Diospyrus Ebenus and D. Ebenaster, yields respectively Mauritius ebony and the BASTARD EBONY of Ceylon. Pale-coloured woods are stained in imitation of ebony (FACTITIOUS EBONY), by washing them with or steeping them in a strong decoction of logwood or of galls, and, when dry, washing them over with a solution of sulphate or acetate of iron. They are then rinsed in clean water, and the process is repeated, if required. The wood is lastly polished or varnished.

EBRI′ETY. See Intoxication.

EBULLI′′TION. The state of boiling, or the agitation of a liquid arising from its rapid conversion into vapour by heat. Ebullition occurs in different liquids at very different temperatures, such temperatures being called their ‘boiling-points.’ Under the same circumstances the boiling-points are constant, and by observing them the chemist is often able to distinguish liquids which much resemble each other. The boiling-point of the same liquid may, however, vary considerably under different circumstances. The causes which induce variation are increased or diminished atmospheric pressure, the greater or less depth of the liquid, and the character of the containing vessel. Thus boiling water is colder by some degrees when the barometer is low, in bad weather, or at the top of a hill, than when the barometer is higher, in fine weather, or at the bottom of a valley or mine. There is a very simple and beautiful experiment, illustrative of the effect of diminished pressure in lowering the boiling-point of a liquid. A little water is made to boil for a few minutes in a flask or retort placed over a lamp, until the air has been expelled, and the steam issues freely from the neck. A tightly fitting cork is then inserted, and the lamp at the same moment withdrawn. When the ebullition ceases, it may be renewed at pleasure for a considerable time by the affusion of cold water, which, by condensing the vapour within, occasions a partial vacuum. Liquids in general boil from 60° to 140° lower than their ordinary boiling-points when heated in vacuo.

The following table furnishes very exact information respecting the effect of increasing pressure upon the boiling-point of water:—

Boiling water contained in a deep vessel is hotter than that in a shallow one, on account of the greater resistance in the one case than the other to the escape of the steam. It is also found that fluids boil at a lower temperature and more quietly in vessels with rough and spicular surfaces, than in those with smooth or polished ones. The boiling-point of water, as marked on the scale of the thermometer, is 212° Fahr., but in glass vessels, under common circumstances, it varies from 212·254° to 215·6°; whilst in perfectly pure and smooth glass vessels water may be heated to 221° Fahr. without boiling. That the elevation of the boiling-point in this case is due to the nature of the surface, may be at once demonstrated by throwing into water, about to boil in a glass matrass, a little iron filings or coarsely powdered glass, when ebullition will commence with almost explosive violence, at the same time that the temperature of the fluid will sink about 2° Fahr.

Table I.—Boiling-points of Water at different
Pressures. By Mr C. Greville Williams.

Boiling-point
° Fahr.		Barometer
Inches.		Boiling-point
° Fahr.		Barometer
Inches.
18416·67620023·454
18517·04720123·937
18617·42120224·441
18717·80320325·014
18818·19620425·468
18918·59320525·992
19018·99220626·529
19119·40720727·068
19219·82220827·614
19320·25420928·183
19420·68721028·744
19521·12421129·331
19621·57621229·922
19722·03021330·516
19822·49821431·120
19922·96521531·730