THE COMPOSITION OF FRUITS 5 



many other orchard fruits, averaging .264 to .250 per cent of 

 ash in the whole fruit, while prunes averaged .480; plums, 

 .535; apricots, .508; oranges, .432; lemons, .526; cherries, 

 .482; and grapes, .500 per cent of ash. 



The ash of apples averages over one-half of potash, not 

 unlike the other fruits; however, the analysis shows rather 

 more variation for ash than has usually been noticed in the 

 fruits in general. The same remark may be made as to 

 variation in quantity of P2 O5, the next largest and most 

 important ingredient. But, on the average, this amount is 

 found to be much like that in the ash of oranges, figs, and 

 apricots, which contain upwards of 12 per cent of phos- 

 phoric acid; as against 21.24 per cent for the grape, 15.1 

 for cheny, and 14.1 of phosphoric acid for the prune. 

 There is about 4 per cent lime in the ash of apple, and 

 a similar amount in the ash of cherries, apricots, prunes, 

 and grapes. The ash of oranges and lemons contains about 

 five times as much as that of the apple. 



Colby, in speaking of fruits grown under California con- 

 ditions, says, "The figures found for apples (and pears) 

 are, on the whole, so much smaller than those which have 

 been obtained for the other ordinary orchard fruits, that it 

 would seem safe to conclude that here fertilizers will not be 

 necessary for apple crops for many years to come. However, 

 the figures do indicate that the first need will be for a nitrog- 

 enous fertilizer. Along with this need will come that for a 

 phosphatic fertilizer. There is no reason to supply potash to 

 apple orchards for a great many years to come. " 



4. Forms of sugar in fruits. — There is not absolute uni- 

 formity in the method of expressing the sugar-content 

 of fruits. In general, however, two kinds of sugar are 

 present, sucrose and invert or reducing sugars. The sucrose 

 is mainly cane-sugar (C12H22O11), while the invert sugars or 

 dextrose group (C6H22O11) consist of glucose (dextrose), 



