CHEMISTRY OF THE CROP. 451 



More recently, Dr. Voelcker and Dr. Anderson have 

 investigated the organic composition of the bulb grown 

 respectively in England and in Scotland. Their deter- 

 minations agree very closely with each other, and also 

 with that of Dr. Fromberg, so as to give us a perfectly 

 reliable estimate of the amount of nutritive matter fur- 

 nished by the crop. Dr. Voelcker gives the results of his 

 analysis thus : 



Compounds containing nitrogen (flesh -f ormers) , 1'81 



Compounds destitute of nitrogen (heat-givers and fat-formers), ... 1T19 



Ash (mineral matters), '96 



Water, 86*04 



ico-oo 



Dr. Anderson's l attention had been called to an opinion 

 that existed, that the portion of the root growing above 

 the ground was superior in feeding value to that portion 

 beneath the surface; he therefore carefully divided the 

 roots subjected to analysis into their respective portions, 

 and determined their composition separately. In the two 

 varieties experimented upon a marked difference was seen 

 between the nitrogen compounds (the only object sought 

 for) of the two portions of one variety, the Long Yellow, 

 but so slight a difference in the other, the Long Red, as 

 practically to be of no importance; therefore, although 

 we are quite right in assuming that that portion of vege- 

 table bodies exposed to the light contains more nitrogen- 

 ous substances than the portions covered up and deprived 

 of light (as is shown in the analysis of the cabbage crop, 

 p. 389), still the difference, if it really exists as a rule in 

 the mangold, would but little affect its cultivation, as for 

 other reasons of a practical nature, the general opinion is 

 in favour of those varieties which carry the bulk of the 

 produce above the ground. 



1 High. Soc. Trans., 1855, p. 276. 



