326 THE TURNIP CROP. 



we have placed at our disposal reliable information upon 

 every point of its composition and requirements. In a 

 plant subject to such different modes of treatment as the 

 turnip, its general composition and the relative propor- 

 tion of its constituents are necessarily liable to great varia- 

 tions the difference produced in it by a wet or dry 

 season, by poor or rich soils, by slow or rapid growth 

 induced by the absence or presence of stimulating manures, 

 by far exceed that which is always, to a certain extent, 

 found due to the influence of descent from different varie- 

 ties. For this reason it is not possible to assign any fixed 

 or determinate feeding value to this valuable root ; all we 

 should attempt is an estimate based upon our knowledge 

 of its general composition, and upon the degree of deve- 

 lopment of the individual plant or crop. In an investi- 

 gation involving such chances of difference as must .ever 

 exist in the composition of our root crops, the result of a 

 solitary determination is of but little value, as it may 

 represent a condition that may not occur elsewhere ; it 

 may be correct as regards the individual, but incorrect 

 as regards the mass. In the systematic investigation by 

 Messrs. Way and Ogston, 1 into the ash-analyses of turnips, 

 we have the results of their examination of above 100 

 specimens, embracing all the ordinary varieties, and grown 

 in well-nigh every variation of soil and climate. From 

 these we can safely deduce average results, which pro- 

 bably would give us more reliable evidence as to the 

 general composition and requirements of the crop, than 

 we could, except at a great outlay of time and money, 

 obtain from any special examination. In determining the 

 proportion of water contained in the "bulbs" of thirty spe- 

 cimens of different varieties, it was found to vary from 

 8G to 92 - 77 per cent., giving an average of 90 per cent., and 



1 Full details of this important and interesting investigation are given in the 

 Roy. Ayri. Soc. Jour., vol. viii. p. 134. 



