Professor Goessmann, in discussing the ash of fruits, gives the following analysis of the ash of the Baldwin apple; this would represent the mineral matter taken from the soil by the fruit: Potash, 63.54 per cent.; soda, 1.71; lime, 7.28; magnesia, 5.52, and phosphoric acid, 20.87. Comparing this with the ash of other fruits, it is seen that the amount of potash required is larger than in the case of other fruits except plums and peaches, and the amount of phosphoric acid is high, but not as high as in the case of some berries. The application is obvious; in order to successfully raise apples there must be an abundance of potash and of phosphoric acid in the soil, and these ingredients must be in an available form. If we compare the apple and the pear by an analysis for fertilizing constituents, or such constituents as are usually introduced into deficient soil by means of fertilizers, we have the following table: 1000 parts of the fruit contain, in the case of each, H2O N Ash K2O Na2O CaO MgO P2O5 SO3 SiO2 Apple 831 0.6 2.2 0.8 0.6 0.1 0.2 0.3 0.1 0.1 Pear 831 0.6 3.3 1.8 0.3 0.3 0.2 0.5 0.2 0.1 When we study the composition of the apple, to determine the "proximate principles," as they are called, it is noticed that we have the constituents mentioned in the discussion of the elements contained in the fruit combined to form various substances; thus: Apples. Pears. Cherries. Peaches. Water 82.04 83.95 75.73 84.99 Sugar 6.83 7.00 13.11 1.58 Free acid .85 .07 .35 .61 Albuminous substances .45 .26 .90 .46 Pectous substances .47 3.28 2.29 6.31 Soluble 14.96 10.90 17.25 9.39 Free acid in fruits is not neutralized by sugar, but it is well known that an abundance of sugar will cover up the sour taste of a fruit. The constituents above noted are mostly found in the expressed juice of the fruit, and give it its characteristic flavor. Without the sugar in these juices it would not be possible to make any alcoholic beverages from them. In the process of fermentation, in the case of apple juice, we have first the change of the sugar to alcohol and carbonic-acid gas, which imparts to cider its characteristic taste and tang. Afterwards, the alcoholic solution, in the presence of the organic matter, is subjected to what is called acetic fermentation; that is, the vinegar plant grows at the expense of the organic matter in the cider, and this beverage is converted into vinegar, containing acetic acid. It is a familiar fact that the change does not readily take place except when cider is exposed to the air, and this is shown to be true from a chemical standpoint, as the cider really is oxidized to make the vinegar; that is, it takes up oxygen from the air.