514 Agricultural Chemistry — Turnips. 



salt much greater; but that of the important constituent and 

 agent, superphosphate of lime, is diminished. The result is a 

 very great depreciation, not only in number of plants, but in the 

 average weight of bulbs. 



We have now given and examined the results of the first two 

 seasons of our experiments upon the joint effects of climate and 

 manures on the growth of the turnip bulb : and comparing the 

 general character of the one season and its results with that of the 

 other, we see, that although the climatic or vehicular and accu- 

 mulative agencies were, during the largest portion of the time of 

 growth, more favourable in 1844 than in 1843, yet the produce 

 was, in the main, much inferior under the superior circumstances 

 of climate. This can only be attributed to deficiency in some 

 essential agency or supply, apart from those of season alone ; and 

 since those instances in this season, in which mineral supply is 

 most liberal, show by the number of plants a degree of healthy 

 condition, and yet an inferior rate of growth, we conclude that 

 the soil was exhausted of matter for organic formations. That 

 the defect is carbonaceous rather than nitrogenous, is learnt from 

 a careful comparison of the effects of rape- cake and of am- 

 moniacal salts. 



Again, the conclusions elicited by a close examination of this 

 second year's experiments, are seen to be identical in kind with 

 those to which we were led by the first year's results ; and in 

 their degree afford even clearer testimony — rather than mere con- 

 firmation — on most of the points which had been previously dis- 

 cussed. It is the less important, however, to give a recapitulation 

 in this place, as we have yet the entire results of the third 

 season (1845) to detail ; and, having accomplished that part of 

 our task, we shall be prepared to give a resume of the three years' 

 series. 



The destructive effects of some substances, when applied near 

 to the seed, led us to sow the manures and the seed separately in 

 the third year of our experiments. The same division into plots 

 was observed as previously ; but besides the drilled manures, 

 which, though for the most part mineral, were sown before the 

 seed, and at a somewhat greater depth, the entire series of plots 

 was crossed by bands 72 yards in width ; which were sown 

 respectively with rape-cake, ammoniacal salt, and rape-cake and 

 ammoniacal salt together, a sufficient portion being left having 

 drilled manures only. These cross-dressings were sown broad- 

 cast, before the ridges first drawn out had been split and turned 

 over, so that there could be little danger of injury to seed and 

 young plants. By this arrangement of manuring, for each of the 

 more than 20 conditions of ' ash-constituent ' supply, 4 of varying 



