330 THE TURNIP CROP. 



results were obtained : they afforded a nearer approxima- 

 tion to the value of the whole turnip, as there appears to 

 be a tolerably consistent relation between their specific 

 gravity and the proportion of nitrogen compounds con- 

 tained in them. Dr. Anderson, 1 to whom the investiga- 

 tion was confided, sums up his report by stating 1st, 

 That the specific gravity of the whole turnip cannot be 

 accepted as indicating its real nutritive value, the pro- 

 portion of air in the cells being the determining element 

 in such results; 2d, That there is no constant relation 

 between the specific gravity of, and the nitrogen com- 

 pounds in the bulb ; and 3d, That such relation does exist 

 between the specific gravity of the expressed juice and 

 the nitrogen compounds and solid constituents; conse- 

 quently, we may rely upon this as indicative of the true 

 feeding values of the several varieties tested. 



This investigation, though failing to confirm the original 

 views, has been productive of much practical good ; as we 

 now know that difference in specific gravity of the whole 

 root is due to the proportionate presence of air in the cells ; 

 consequently, that those varieties containing the least are 

 the best adapted for keeping. Hence it is that the Swede 

 is of all the varieties the best for storing away, and that 

 the hybrids and the yellow are superior to the white 

 varieties, which have the lowest specific gravity, and 

 contain the largest amount of air in their cellular tissue. 

 Thus the determination of the specific gravity of the 

 entire bulb gives us its relative keeping properties, and 

 the specific gravity of the expressed juice indicates at 

 once the real feeding value of the specimen examined. 

 These results are perfectly in accordance with those ob- 

 tained by M. L. Vilmorin, 2 in France, in reference to the 



1 Details of this important investigation are given in the Trans, of High. Soc., 

 1856, p. 184. 



2 Instruction pour VEssai des Betteraves, par L. Vilmorin. Jour. d'Agri. 

 Pratique, 1858. 



