548 



Agricultural Chemistry — Turnips. 



about 60 lbs. of nitrogen by manure, we have a percentage of 

 2*86 in the dry matter of the produced bulb, whilst in the fourth 

 column, with a supply of about 110 lbs. per acre, we have only 

 2*33 per cent. ; but when we remember that in the latter case 

 there was a large amount of carbon in the manure, and in the 

 former none, we have a clear illustration of the close connexion 

 between the provision by manure and the composition of the pro- 

 duce. To render our meaning more intelligible we may further 

 explain that the nitrogen in the turnip, and indeed in food- 

 products generally, exists in combination with carbon, hydrogen, 

 and oxygen, itself comprising nearly one-sixth part of the thus 

 constituted nitrogenous compound ; the remainder of the dry 

 matter consists of the compounds destitute of nitrogen, of which 

 the chief constituent is carbon. Now in column 3 there was no 

 carbon in the manure, but in column 4 a large amount was pro- 

 vided in the rape-cake, and notwithstanding that there was in this 

 case not only the same amount of nitrogen supplied by ammonia 

 salt as in column 3, but further, all that of the rape-cake, raising 

 the total amount to nearly double, yet the supply at the same 

 time of carbon favouring the formation of non-nitrogenous com- 

 pounds, gives a less proportion of those which are nitrogenous. 



Again, if we compare the mean of these results with the mean 

 percentage of dry matter under the four conditions of manuring, 

 we find with the lovv^est per centage of nitrogen in the bulb the 

 largest amount of dry matter, and with the highest percentage of 

 nitrogen the lowest amount of dry matter. There is then with 

 the highest percentage of nitrogen more of circulating fluid and 

 less of fixed deposited substance than with the lowest ; and since 

 there was moreover not only a less matured bulb, but a less 

 acreage produce of it in a given time than where the nitrogenous 

 supply was less, we are led to infer that the high percentage 

 of nitrogen indicates a relative deficiency of carbonaceous sub- 

 stance, rather than a favourably increased amount of nitrogen. 

 Indeed these results will confirm the opinion already urged, 

 namely, that turnip-bulb formation is very dependent on an 

 abundant supply of carbonaceous matter to the roots, and that the 

 more the nitrogenous condition of manuring prevails over the 

 carbonaceous, the more will vascularity and the less will special 

 deposition be enhanced. Thus the highly vascular seed-forming 

 turnip-plant is to the less vascular bulb-forming one, as the well- 

 conditioned breeding or working animal is to the stall-fed fatting 

 one; a considerable amount of nitrogenous as well as carbo- 

 naceous food is essential to both of these ; in the one case, how- 

 ever, exercise tends to consume what in the other increases the 

 bulk of the animal : so that whilst the food taken may indeed in 

 the two cases be very similar, yet the balance of it retained in 



