26 



VOELCKER on the Chemistry of Food. 



" This table shows that, both as respects the organic and inor- 

 ganic constituents, the thin liquid is equal in nutritive value to 

 half its weight of turnips ; and the thicker liquid to fully its own 

 weight of the same root." 



These analyses thus fully demonstrate the value of this refuse 

 as food, especially for dairy cows. 



6. ROOTS (Potatoes, Parsnips, Carrots, Swedes, Mangolds, and 

 Turnips). All the roots which are grown as food for man or 

 beast are distinguished from most articles of food described 

 above by a large amount of water. The proportion of water in 

 roots varies in the different species from 75 to 90 per cent., and 

 it is principally on account of the small amount of solid matter 

 that roots are much less nutritious than an equal weight of most 

 of the feeding materials which have been described above. 



We shall mention first the composition of potatoes ; then state 

 that of carrots and parsnips \ next, that of mangolds ; and lastly, 

 in a separate table, the average composition of swedes and turnips. 



Potatoes. The different species of potatoes vary considerably 

 in composition, and even one and the same variety of potatoes, 

 when grown on different soils, or with different manures, or, in 

 short, under different circumstances, will exhibit great variation 

 in its composition. Since this is the case, it would be of no 

 practical value to transcribe here the analyses which have been 

 made with the various species of potatoes that are cultivated in 

 this country. We shall, therefore, leave these details unnoticed, 

 and state at once the average composition of potatoes, as calcu- 

 lated from a great number of the most trustworthy analyses. 

 Average Composition of Potatoes, in round numbers. 



