According to the analyses of Moritz, the maximum and minimum relative proportions of the constituents of natural wine are as follows:--The extract (after deducting the free acids) ranges from 1·10 to 1·78 per cent.; the proportion of ash to extract varies from 1 : 19·2 to 1 : 6·4; that of phosphoric acid to ash ranges from 1 : 12·3 to 1 : 10·49; that of alcohol to glycerine, from 100 : 12·3 to 100 : 7·7.[110] From the investigations of Dr. Dupré, it would appear that in genuine unfortified wines, the amount of alcohol present varies from 6 to 12 per cent. by weight. A wine containing less than 6 per cent. would be unpalatable, and more than 13 per cent. cannot well be present, since natural grape-juice does not contain the quantity of sugar requisite for the production of a greater amount of alcohol; moreover, an excess of this proportion would retard, if not entirely stop, the process of fermentation. Pure wines contain a greater proportion of volatile than fixed ethers, but in fortified wines the reverse is frequently the case. In natural wines, which are not over a few years old, the sugar present rarely amounts to 1 per cent., generally it is much less. Fortified wines, in which fermentation has been checked by the addition of alcohol, often contain 5 per cent. of sugar; champagnes usually show from 4 to 10 per cent., and, in some liqueur wines, a maximum of 25 per cent. has been found. In natural wines, the total dry residue generally ranges from 1·5 to 3 per cent., while in fortified wines the addition of sugar and other substances may increase its proportion to 10 per cent., or even more. At the Paris Municipal Laboratory the following standards are adopted: The amount of added water in all wines, not sold as of a special or abnormal character, is calculated on a basis of 12 per cent. of alcohol (by volume) and 24 grammes of dry extract per litre. The proportion of potassium sulphate in unplastered wines must not exceed 0·583 gramme per litre. The use of salicylic acid is prohibited. FOOTNOTES: [87] During the year 1886 the total production of Californian wine approximated 19½ million gallons, of which 3½ million gallons were consumed in the manufacture of brandy, and 5 million gallons exported. [88] These figures denote the weight in grammes of the ingredients contained in 100 c.c. of the wine; otherwise, percentages are expressed. [89] Berichte der Deutsch. Chem. Gesell., 1885, p. 426. [90] Zeit. f. Anal. Chem., 1885, p. 44. [91] Repert. Anal. Chem., 1882, ii., p. 1. [92] ‘Comptes Rendus,’ xcviii. p. 110. [93] _Vide_ ‘Spon’s Encyclopædia.’ [94] Jay, Bullet. de la Soc. Chim., xlii. p. 217. [95] Dict. des Falsifications. [96] ‘Les Mondes, Revue Hebd. des Sciences,’ No. 4, 1876. [97] Bullet. de la Soc. de Chim., xlii. pp. 167 and 207.