The clarified wine, treated with an equal volume of saturated baryta water, and filtered after standing for fifteen minutes, gives a dirty yellow, or slightly greenish filtrate.

With an equal volume of aluminium acetate of 2° B. it gives a lilac wine-coloured filtrate.

With a few drops of aluminate of potash no change of colour. With sodium carbonate, employed as at C., the liquid tends to lose its colour on heating. With barium peroxide, used according to Table A, column P, the liquid is faintly rose-tinted, with or without an orange-coloured deposit on the barium peroxide. NATURAL WINE.

With the general characters above indicated, if with baryta water it affords a madeira-coloured filtrate, changing to buff on acidulation with acetic acid; if with borax it becomes deep-green with a bluish cast; if with alum and sodium carbonate (as at E) a precipitate falls of a deep bottle-green, with bluish tinge, and if with aluminium acetate it remains rose-coloured with no change to violet-blue. TEINTURIER.

By treat-
With a

(b.) The liquid is reddish-yellow or brown-lilac. ment with acetate of alumina the filtrate is clear lilac. few drops of aluminate of potash the colour becomes that of the skin of an onion, and with a larger quantity of the reagent the colour is green, tinged with maroon. With sodium carbonate (employed as at C.) the fluid passes to yellowish or greyish-yellow, with tinge of red. With barium peroxide, flesh-coloured liquid with considerable orange-coloured deposit in contact with the peroxide. BEETROOT, fermented or not.

(c.) The liquid is yellowish-grey, with tinge of green or red. With baryta water the filtrate is yellowish olive-green. With aluminium acetate the filtrate is bluish-violet, or violet-lilac. With aluminate of potash, fresh rose, becoming yellowish-green, with an excess of reagent. With sodium carbonate (as at C.) the fluid becomes deep grey on heating. With barium peroxide the fluid is bleached, or remains but very slightly roseate, with a trace of orange deposit in contact with the peroxide. WHORTLE

BERRIES.

M. The mixture of wine and alkaline carbonate C. (b.) is heated to boiling.

LOGWOOD.

(a.) The mixture becomes lilac-violet, or violet. (6.) The mixture tends to become decolorised, or changes to yellowish-green, or dark green, or maroon green, natural wines, whortleberries, both elders, privet, Portugal berries, fuchsine. Pass to N.

N. Treat the wine with alum and sodium carbonate, as directed at E., and filter.

(a.) The colour of the filtrate is lilac. Portugal berries. (b.) The filtrate changes to bottle-green, or reddish-green. Natural wines, whortleberries, hollyhock, privet, both elders, fuchsine. Pass to O.

O. Treat 2 cc. of the clarified wine with 3 or 4 cc. of a saturated solution of borax, according to the intensity of the colour of the wine.

(a.) The liquid remains wine lilac, or with some violet tinge, both elders, privet, whortleberries. Pass to P.

(b.) The fluid becomes bluish-grey-flax-blossom, greenish or bluish-grey, with very faint trace of lilac, pure wine, whortleberries, hollyhock, fuchsine. Pass to R.

P. Treat a new portion of wine with sodium bicarbonate (as directed at I.).

(a.) The tint, at first lilac, changes afterwards to grey, slightly brownish, or to maroon. If a new portion be treated with sodium carbonate, according to C., and then heated to boiling, it becomes clearer, and loses its green tint.

The lake obtained according to E. is deep blue-green. ELDER.

DWARF

(6.) The specimen remains grey, tinged with green, bottlegreen, or yellowish. Sometimes (black elder) it acquires a lilac tint, which almost immediately disappears, changing to a greenish-grey-blue, whortleberries, black elder, privet. Pass to Q.

Q. Treat a specimen of the wine with alum and carbonate of soda (as directed at E.). Shake the mixture, and after a few moments throw it on a filter.

(a.) The lake remaining on the filter is deep green-blue; the filtrate is clear bottle-green. A sample treated with sodium carbonate (as at C.) darkens and becomes grey, slightly greenish, on heating to boiling. BLACK ELDER.

(b.) The lake is clear bluish or greenish. The filtrate is clear bottle-green. A sample treated with sodium carbonate (as at C.), and heated to boiling, changes to dirty yellowish. PRIVET.

(c.) The lake is ash-green faintly rose-tinted. The filtrate is bottle-green, with tint of maroon. A sample treated with sodium carbonate (according to C.) becomes deep grey on being heated to boiling. WHORTLEberries.

R. Treat a specimen of the wine with ammonia and ether, as directed at J.

(a.) The ether being decanted and evaporated, the fluid residue becomes rose-coloured on treatment with acetic acid. FUCHSINE.

(b.) The liquid left after the evaporation of the ether does not become red on acidification with acetic acid, natural wines, hollyhock, whortleberries. Pass to S.

S. A sample is treated with its own bulk of a solution of aluminium acetate of 2° B.

(a.) The colour of mixture remains winey, natural wines, whortleberries; differentiate between them, as directed at L (a), and L (c).

(b.) The colour of the mixture becomes violet-blue, hollyhock, whortleberries. Pass to T.

T. A specimen is treated with alum, and sodium carbonate (as at E.), and after a few moments filtered.

(a.) The lake is clear green, slightly bluish, and rose-tinted; filtrate is bottle-green, with little maroon. With borax (as at O), particularly if the sample has been concentrated, the liquid is grey with trace of lilac. 2 cc. of the liquid treated with 3 cc. of dilute ammonia (1 vol. of liq. ammonia with 10 vols. of water), and the mixture diluted with its own bulk of water, gives a liquid which is yellowish-grey, greenish or greenish-grey. The other characteristics as at L. WHORTLEBERRIES.

(b.) The lake is green, slightly bluish, quite free from rose, filtrate clear bottle-green. With borax the liquid is greenish blue-grey. With ammonia (as above), dark bottle-green. With aluminium acetate (as at S.), bluish-violet coloration. HOLLYHOCK.

Although somewhat difficult, this systematic method serves for the discovery of several colouring-matters mixed in one wine, if the indications of Tables A. and B. are carefully observed and followed. It is always desirable to determine the presence of fuchsine by the special reactions given further on. By means of Table B. the presence of one or several of the colouringmatters may be detected; but before deciding, it is as well to verify by repeating, for the substances so found, the reactions of Table A. on the sample; and also the more special characteristics given further on, for the identification of those substances.

SPECIAL REACTIONS FOR THE DETECTION OF CERTAIN OF THE

COLOURING-MATTERS MIXED WITH WINES.

Brazil Wood.-Even a very strong clarification (two or three times more albumen than mentioned at the head of Table B.) does not wholly decolorise the adulterated wine. It becomes yellow-buff, which on exposure to the air gradually changes to red.

If a wine that has been adulterated with Brazil-wood is clarified, and then a skein of scoured silk, washed with dilute tartaric acid, be soaked in it for twenty-four hours, and then withdrawn, washed, and dried at 60° to 70°, the silk will be found to be dyed lilac-maroon, or red. In pure wine, the skein remains wine-coloured or lilac.

If the dyed silk be now dipped into dilute ammonia, and heated to 100° for a moment, it becomes lilac-red, if Brazil-wood were present; but deep grey, with scarcely a tinge of its original colour, if the wine were pure. If the ammonia be replaced by lime-water, the skein changes to ash-grey if Brazil-wood were present; but to a dark, dirty-yellowish-red, if the wine were pure. Finally, if the skein be dipped into aluminium acetate, and then heated to 100°, it retains its wine-red lilac colour. This reaction differentiates Brazil-wood from logwood.

Logwood. If the colour due to logwood is in excess in the wine, ammonia gives it a shade of violet; if the proportion of logwood is small, the reactions B, L, N, of Table A., which are very delicate, should be tried.

A skein of silk, prepared in the manner described for Braziwood, and treated with logwood, becomes dyed lilac-red, or maroon, which dilute ammonia changes to violet-blue tinged with grey, and which by acetate of aluminium becomes bluish-violet.

Cochineal. The lilac, or roseate tints due to the reactions A, B, H, K, of Table A., are very sensitive, the last being very characteristic; the only substance likely to be confounded with it is the phytolacca (Portugal berries), which is differentiated by the reaction B, of the same table.

A skein of scoured silk, mordanted with aluminium acetate soaked in the clarified wine for twenty hours is dyed of a wine violet colour, analogous to that of pure wine, on being dried at 100°. The colour does not change, even at 100°, by cupric acetate (exclusion of fuchsine); but if the skein be dipped into a dilute solution of zinc chloride, heated to 100°, and then wetted with sodium carbonate, washed with water and dried, the colour becomes fine purple, whereas with pure wine the tint would remain sombre grey-lilac.

Cochineal may be discovered by the spectroscope if present in large quantity, but if it amounts to only about 12 per cent. of the total coloration, it cannot be so detected. It rapidly separates from wines, being precipitated in the lees.

Fuchsine. This should be sought for in all wines found to be adulterated with other substances. The reaction J of Table B., p. 572, is very sensitive. Great care must be taken to avoid loss of rosaniline from imperfect decomposition of its salts in solution; moreover, arsenic should always be sought for where the wine is found to contain any aniline. Fuchsine rapidly separates from the wines to which it has been added. A skein of silk becomes dyed rose by soaking in a wine adulterated with fuchsine, and its colour passes to yellow on treatment with hydrochloric acid, but to bright red if the wine was pure. The dyed skein

treated with dilute cupric acetate, and dried at 100°, becomes fine deep rose-violet if fuchsine is present, and of a lilac tinged with ash-grey if the wine is pure. This reaction is very

sensitive.

Phytolacca.-(Portugal berries). The rose or lilac colorations of the reactions A, G, and especially C of Table A., are very sensitive.

Hollyhock (Althea rosea), much used. This substance imparts a peculiar flavour, which in a few months becomes actually disagreeable, while the colouring-matter itself rapidly precipitates. Beetroot. This is generally employed only to mask other adulterants. The lilac tint of reaction C of Table A., if the beetroot is fresh, and the yellowish colours due to alkalies (reactions D, E and F of Table A.) are very sensitive, even with old decoctions.

Black Elder, Dwarf Elder.-The dwarf elder imparts a faint turpentine odour to the wines. The berries of both varieties are particularly used to communicate a special colour and flavour to port wine. The teinte de Fismes, (p. 565), largely used at Fismes, Paris, and elsewhere, is made by digesting 250 to 500 parts of elder-berries, and 30 to 60 parts of alum, with 800 to 600 parts of water, and then submitting the mixture to pressure. M. Maumené reports having discovered as much as 4 to 7 grms. of alum per litre in wines adulterated with this substance. Sometimes (though rarely) the alum is replaced by tartaric acid. Wines adulterated with either yield a violet-blue lake (reaction H, Table A). By comparison with pure wine the difference is very marked.

A piece of flannel, or skein of silk, mordanted with aluminium acetate, heated for some time in the suspected wine, then washed, and immersed in water made faintly alkaline with ammonia, becomes green if the wine is pure, but dark brown if black elder is present. Probably the same reaction occurs with dwarf elder. Privet. This is seldom used. The general reactions, particularly N and P of Table A., may be referred to (see also footnote, p. 571).

--

Kino.-Said to be coming into use. It is precipitated by gelatin, and gives no definite absorption bands. According to Etti kino-red is the anhydride of kinone, and has the formula C28H22O11

*

Indigo.-The reactions A (b) and B (b) of Table B., p. 570, are so sensitive that they are alone sufficient to characterise indigo. Wool or silk mordanted with aluminium acetate, heated with 20 to 40 cc. of the suspected wine nearly to dryness, washed, and *Deut. chem. Ges. Ber., xi., 1883, s. 1879.

(UNIVERSITY