382 



BOTANY OF CROP PLANTS 



hours, Reinettes, Stripelings, Pointlings, and Flat apples. 

 Beach gives the following groups of varieties: Fall Pippin, 

 Rhode Island Greening, Winesap, Fameuse, Alexander or 

 Aport, Wealthy, Duchess of Oldenburg, Northern Spy, 

 Blue Pearmain, and Rails-Genet. 



Compositioti. — According to the determinations of Al- 

 wood and Davidson, the average amount of juice recovered 

 from summer apples by grinding and pressing is 53.2 per 

 cent. ; from winter fruit 53.92 per cent. Crab-apples show an 

 average juice content of 57.31 per cent. The average water 

 content of the whole apple varies from 80 to 86 per cent, of its 

 total weight. It is not possible, of course, to remove all the 

 juice from apples by ordinary pressing, -and furthermore, the 

 amount of juice recovered depends upon the grinding and 

 pressing methods. The above workers chemically analyzed 

 the juice and pomace of many varieties. The percentage 

 composition of the juice is shown in the following table : 



Specific 

 gravity 



Summer varieties 

 Autumn varieties 

 Winter varieties. . 

 Crab-apples 



Total 

 solids 



1.049 12-33 

 I. 054 13.76 

 1.056 I 14-29 

 1.062 j 15.69 



Total 

 sugar 



9-53 

 10.66 

 II 

 II 



Invert 

 sugar 



S.85 



6-93 



43 ■ 7-04 



71 8.08 



Cane 1 Acids as _, 

 sugar HsSOi ' Tannm 



3-SO 

 3-53 

 4.16 



3-45 



0-33 

 0.36 

 0.41 

 0.50 



0.040 

 0.069 

 0.050 

 0.122 



For vinegar-making, a high sugar content is desirable. A 

 common notion is that acid or "tartar" apples are better for 

 vinegar-making than those low iii acid. The amount of acetic 

 acid in a vinegar, which is the important test of its quality, 

 is dependent upon the amount of sugar in the juice (cider) 

 and not upon the acid. The sour taste of apples is due to the 

 malic acid present. So-called "sweet apples" do not neces- 



