(5.) Bitter principles, occasionally derived solely from the hop, but very commonly supplemented by so-called "hop substitutes." Samples of the latter examined by the author all contained "quassia," and portions of the following plants were identified-Calumba, chirata, gentian, and wormwood.

(6.) The ash derived from the water, the malt, and the bitters.

To these must be added volatile and essential oils, vegetable gelatine, glucinic acid derived from the sugars, lactic acid, and, in porters, caramel and assamar.

The general composition of the chief ingredients of beer may be gathered from the following table, taken from Mr. Watts' Dictionary :

TABLE XXXVI.--SPECIAL EXAMINATION OF CERTAIN BEERS.

The composition of beers, as a whole, varies in some degree according to the kind of ale or beer, according to the method of manufacture, and according to its age and preservation.

Pale Ale should be made from the finest and highest dried malt and the choicest hops, the bitter being in excess.

Mild Ale is a sweet, rather strong beer. Table beer is rarely sold-it is a weak watery ale.

Porter, as drunk in the metropolis, is a rather weak maltliquor, coloured and flavoured with roasted malt. Stout is a richer and stronger description of porter.

The German Beers generally are fermented by sedimentary yeast, and are always, by reason of the after fermentation ("Nachgährung"), well charged with carbon dioxide. The lager, summer, bock, or export beers are separated from the winter beers only by the former being brewed from a richer wort, and containing more alcohol, as well as a greater percentage of malt extract. Bavarian Beers in some degree derive their peculiar qualities from fermentation at a low temperature. They seldom contain more than two per cent. of alcohol, are only slightly bittered, have a fine aroma, and a peculiar flavour, said to be due to the solution of a minute fraction of the resinous matters used to caulk the casks.

Lambick and Faro Beers are made with unmalted wheat and barley malt. In fermentation the wort is self-impregnated, the process sometimes taking months, and being mostly of a bottom character. The beer contains a large quantity of lactic acid, and is very hard in consequence.

Of the constituents of beer, it will be necessary to notice fully the water, the malt extract, the bitters, and the ash.

§ 255. The water used by the brewer is mainly interesting to the analyst on account of the common salt held in solution, since in prosecutions for the addition of salt the defence generally is, that the latter is a natural component of the beer. Thus, Dr. Bottinger's analysis of the constituents of the water used at Messrs. Allsopp's brewery is as follows:

Messrs. Bass and Co.'s water (according to an old analysis of Cooper) contains chlorine equal to a little over 10 grains of common salt per gallon, and all published analyses of water used in breweries give quantities of salt under 14 grains per gallon. However, since breweries, as a rule, use hard spring water, it is quite possible for the water in particular localities to contain a much larger percentage of salt than the quantity mentioned above.

§ 256. Malt Extract.-The constituents of barley and also of malt are given in the following table; but of these it is the ash alone which will remain, comparatively speaking, unchanged; for by the action of mashing a very large portion of the dextrine and starch becomes changed into sugar.

TABLE XXXVII.-COMPOSITION OF BARLEY AND MALT.

Barley contains dextrine, starch, albuminous substances, and a small quantity of fat, together with cellulose, and the ordinary saline constituents of seeds. Malt, varying a little in composition according to the heat of the final operations of the maltster, differs from barley in containing a small quantity of sugar (derived from transformation of a portion of the starch), rather more dextrine, and altogether less organic matter, the loss on malting being usually represented as

The constituents of barley are thus given by Oudemann:—

According to Thomson, the following is the relative composition of the ash of malt and barley:

Valentine and O'Sullivan have recently disputed the correctness of Oudemann's and the older analyses in the following points:-Oudemann finds from 5 to 8 per cent. of dextrine, Mr. O'Sullivan no dextrine at all; the small percentages of sugar generally quoted-viz., up to 10 per cent., Mr. O'Sullivan gives at from 16 to 20 per cent.; and the authors have compiled the following table, stating that each item has been estimated directly, and not by difference:

§ 257. The Colouring-Matters of Malt.-The colouring-matter of malt has been investigated by Sorby, and examined spectroscopically. The colour is of an orange yellow, and may be obtained from the hot water extract of malt, after having got rid of as much sugar and gum much sugar and gum as possible. Ammonia colours it a deeper yellow, so does 50 per cent. sulphuric acid. There is no distinctive spectrum. A special test is to add citric acid to a watery or alcoholic solution, and then sodic hypochlorite. The watery solution under these circumstances becomes flesh-coloured, turbid, and after a time precipitates. The spectrum, according to Sorby, is moderately dark from D E to FG, clearer from there to FG, then moderately dark without estimable narrow bands; but in alcoholic solution, the solution remains clear, and there is a well-marked band at the yellow end of the green, which is at 42 of Sorby's scale (that is, between D E to DE); if the colour is deeper the band is more evident, and goes to D E. These appearances