Composition of Omnf/e Glohe Mangolds, Bulls and Tops. 203 



3. Determination of Woody Fibre and Pectinous Substances. — 

 The second half of the mangokl was reduced into a homogeneous 

 pulp by grating; it on a fine grater. 2000 grains of this pulp 

 were digested with some cold distilled water, and the liquid, 

 containing in solution the sugar and other soluble constituents, 

 after standing upon the pulp for some time, was strained through 

 a piece of fine linen ; the pulp left on the linen was washed 

 with distilled water and pressed as much as possible by hand. 

 The pressed and partially-exhausted pulp was returned into a 

 glass iDcaker and mixed up with a fresh portion of distilled water 

 and treated as before. The process of digestion and washing on 

 linen with distilled water was continued until a drop of the 

 washings on evaporation on a slip of glass left no perceptible 

 residue. 



The fibrous insoluble matter left on the linen after drying at 

 212^ Fahr., consists principally of cellular or woody fibre, and 

 contains but a small amount of insoluble albuminous compounds, 

 dissoluble pectinous matter, and mineral substances insoluble in 

 water. 



4. Determination of Insoluble Albuminous Substances. — A por- 

 tion of the dried crude fibre was burnt with soda-lime, and the 

 amount of nitrogen arrived at was inultiplied by 6^. The per- 

 centage of insoluble albuminous compounds was deduced from 

 the weight of the crude fibre. 



5. Determination of Mineral Substances Insoluble in fFater. — 

 The remainder of the crude dried fibre was reduced to ashes in 

 a platinum capsule, and the amount of ash likewise deducted 

 from the crude fibre. 



6. Determination of Sugar. — The liquid obtained by digesting 

 the pulped mangold with water, and straining through linen, was 

 evaporated to a thin syrup mixed with washed yeast ; this syrup 

 was submitted to the process of fermentation, and the sugar in it 

 converted into alcohol and carbonic acid. As 1 equivalent of 

 sugar yields exactly 2 equivalents of anhydrous alcohol, and 4 

 equivalents of carbonic acid ; the amount either of alcohol or of 

 carbonic acid obtained in the fermentation of a sugary liquid 

 may be used as the basis for calculating the percentage of sugar 

 in such a liquid. 



If the fermentation is carried on with due care and in a proper 

 apparatus, the amount of sugar in mangolds and all roots may be 

 determined with great precision by this process. 



In the following Table the percentages of water, organic matter, 

 ash, and of nitrogen corresponding to the nitrogenous substances 

 in the roots taken from the 9 different experimental plots are 

 given ; — 



