THE DRIED-FRUIT TRADE. 585 
mal, kingdom are gradual and progressive processes. In the tasteless 
state they consist of little more than the substance of the leaf, of vascu- 
lar or woody fiber, filled with a tasteless sap, and tinged with the color- 
ing matter of the green parts of the plant. But after a time this fruit 
becomes sour to the taste, and its acidity gradually increases. This 
formation of acid proceeds for a certain time, the fruit becoming daily 
more sour; the acidity then begins to diminish, sugar is formed, and 
the fruit ripens. The acid rarely disappears, even from the sweetest 
fruits, until they begin to decay ; a considerable portion-of it, however, 
must be converted into grape-sugar as the fruit approaches to maturity. 
From experiments it is known that when unripe fruits are plucked they 
do not ripen if excluded from the access of oxygen, but that in the air 
they ripen, absorbing oxygen and giving off carbonic acid. 
Many fruits pass, in the course of ripening, from a sour to a sweet 
state. Apples, pears, peaches, currants, cherries, &c., are of this kind. 
Most of them even when fully ripe are still a little acid, the mixture of 
sweet and sour in their juices adding to their agreeable and refreshing 
qualities. All such fruits, as a general rule, contain and owe their sweet- . 
ness to the presence of grape-sugar. From many of them this sugar 
can readily be extracted for use; but in generalitis more economical and 
agreeable to employ it in the form of dried and preserved fruits. By 
continuing the conversion of acid into grape-sugar, and at the same time, 
by the rapidity of its action, arresting the natural tendency to decay, 
there is produced upon the fruit or vegetable a twofold effect, viz., me- 
chanical and chemical. or instance, if a piece of apple which it is pur- 
posed to dry is subjected at first to a very hot and dry atmosphere the 
surface moisture is immediately driven off, and a thin, dry film forms, 
which soon increases in thickness, and, as it were, seals up the water 
which is contained in the interior of the substance. All subsequently 
evaporated moisture must pass through this skin, and in so doing the 
juices of the fruit are brought to and deposited upon the surface, and 
the result is the center of the piece is but little affected, while the sur- 
face is hard and incrusted. Fruit dried in this way is always interior 
in color, flavor, and saccharine matter. 
If, on the other hand, the fruit enters into a moderately warm and 
saturated atmosphere, the moisture is liberated so gently that the juices 
are not disturbed and the surface is not incrusted. As the fruit ad- 
vances in the chamber through strata of air gradually increasing in 
dryness and temperature, the evaporation proceeds with corresponding 
rapidity. The water separating uniformly from the solid constituents of 
the fruit, which undergoes at the same time a chemical change, the acid 
and the starchy parts are converted into grape sugar. This chemical 
action has been demonstrated by actual analysis, as well as in theory; 
but what is far more to the point in a business point of view, it is dis- 
tinguishable by the ordinary senses. An apple-pie made from fruit 
evaporated by these processes cannot be distinguished from one made 
from fresh fruit, and yet only one-half of the quantity of sugar is needed 
to sweeten it; and the same fact is true in regard to tomatoes and all 
other fruits and vegetables. Peaches can be soaked in water and 
eaten with cream. In appearance, flavor, and keeping qualities fruits 
and vegetables prepared by this method are vastly superior to those 
dried in the ordinary manner. 
In the various methods of preparing fruit, it has been found that the 
greatest elements of decay are worms and insects, and it has been difti- 
cult to find some means to prevent the development of insect life. The 
inventors of the new process claim to haye accomplished this by the 
