CROPS 139 



Different varieties ehow considerable differences in composi- 

 tion ; thus the solids in the ripe fruit have been noticed to 

 vary from 13-4 to 23*4 per cent., the invert sugar from 5 "3 

 to 11-7 per cent., the free malic acid from 0*26 to I'll per 

 cent., the ash from 0*17 to 0*37 per cent. 



As an average of recent American analyses of several 

 varieties the following is given as the typical composition of 

 ripened apples ; 



Per cent. 



Water ........ 840 



Ash 0-3 



Invert sugar 80 



Cane sugar 4 



Starch O'O 



Cellulose 9 



Lignin . . 0*4 



Pentosans 0*5 



Pectin matter 0*4 



Malic acid (free) 0-6 



„ „ (in combination) . . . . 0*2 



Oil '. . 0-3 



Protein 01 



Undetermined (tannin, &c.) . . . . 0*3 



100-0 



The ash consists chiefly of potassium carbonate, magnesium 

 and potassium phosphates, calcium sulphate, free lime, with 

 traces of common salt, silica, iron oxide, and alumina. 



Fears (Pyrus communis) resemble apples in their chemical 

 composition, but contain less acid and more "crude fibre." As 

 a rule the trees have deeper roots, and thus range over a larger 

 volume of soil for their sustenance. 



Plums (Prunus 8p2).). — Belonging to this genus are many 

 species, including sloes or blackthorn {P. spiiiosa), bullace and 

 Jamsons (P. insititia), various true plums {P. do7nestica), 

 apricots (P. Armeniaca), wild dwarf cherry (P. cerasus), wild 

 cherry {P. avium), almond (/*. amygdalus or Amygdaliis 

 communis), nectarine and peach (P, persica). The fruit con- 

 sists of a central kernel (the true seed), a hard, bony layer 

 surrounding the kernel (known as the " stone " or " pit ") and 



