546 Agricultural Chemistry — Turnips. 



We shall first speak of the composition of the organic or vege- 

 table part of the turnip, and shall endeavour to show its de- 

 pendence on the manures by which the plant is grown, and the 

 probable relative feeding values of different specimens. 



We do not pretend to have reached further than the threshold 

 of this inquiry, but still hope our results may furnish some inter- 

 esting inferences. The organic matter of the turnip-bulb is com- 

 posed of several complex bodies, some of which consist chiefly of 

 carbon, hydrogen, and oxygen, whilst others contain nitrogen in 

 addition to the other three elements. Other substances, such as 

 sulphur and phosphorus, are also found in these compounds, but 

 in small quantities, and their presence or absence is immaterial 

 to us just now. 



Those of the compounds which contain nitrogen are in less 

 proportion in plants than those in which it is absent; but nitro- 

 gen is a very important constituent in all food, so much so indeed 

 that the comparative feeding value of different articles of produce 

 may frequently be estimated by the amount of nitrogen they con- 

 tain ; and we shall, to some extent, act upon this assumption in 

 what we are about to detail. 



Those who have read the paper on Agricultural Chemistry in 

 the last Number of this Journal, will bear in mind the remark- 

 able fact there indicated, that the larger the amount of the nitro- 

 gen supplied by manure for the growth of wheat, the less v/as 

 the percentage of that substance in the produced grain. This 

 is not consistent with the views generally maintained on this sub- 

 ject, but it seemed to us not only sufficiently proved by our ex- 

 periments — but, when it was remembered that wheat-grain was 

 peculiarly a starchy seed, and that starch contains no nitrogen, it 

 was thought that whatever tended to the healthy action of the 

 plant (as nitrogenous manures were found to do) would of neces- 

 sity develop the special aim and products of the plant, and that 

 in fact it was more natural to expect that the seed would under 

 these circumstances be more starchy than that it would be more 

 nitrogenous and less starchy. In growing wheat-grain^ then, by 

 means of nitrogenous manures the percentage of nitrogen in the 

 produce was rather diminished than increased. The following 

 results will show whether a similar effect is observed in the 

 growth of turnip-bulbs : — 



This is not the place to give any detailed account of our methods 

 of analysis, but we may say that we think considerable confidence 

 may be placed in the results, as a comparative series ; and we 

 believe them to be, moreover, not wide of the exact truth. If we 

 had to give an opinion, however, as to the probable direction and 

 extent of any error, we should suspect it to be in defect rather 

 than in excess, and that if it exist it is pretty uniform throughout 



