1864.] CHEMISTRY OF MANURES. 201 



and crudest enunciations of that doctrine, ever committed himself 

 to the fiillacy imputed to him by the upholders of the rival sys- 

 tem. If he did, he has long since abjured his error ; or rather it 

 has fallen, Uke a deciduous leaf, in the gradual ripening of his 

 opinions during more than twenty years of experiment and 

 research. The reporter believes that, upon this point, there exists 

 at the present time but little real diflference between the views of 

 the contending parties ; i. e., between those who affirm that the 

 ashes removed in the crop do, and those who maintain that they 

 do not, represent the return to be made to the soil, to keep up its 

 fertility. No two opinions, certainly, can seem more diametrically 

 opposed than these; and at the outset of the controversy, the 

 opposition was not only apparent but real. But for many years 

 past, the disputants have bC' n gradually approaching each other, 

 by approaching the great central truths which lay between 

 them. By the dropping, on both sides, of some earlier crudi- 

 ties, often perhaps rather of phrase than thought, and by the 

 discussion, by common consent, of matured opinions only, many 

 of these truths will, the reporter is convinced, be found expres- 

 sible in terms acceptable to both. 



With reference, for example, to the effect of cinereal manuring, 

 both parties will certainly admit that, whether soils be rich or 

 poor, they derive (coeteris paribus) from equal increments of their 

 cinereal stock, equal absolute benefit ; to be manifested, sooner or 

 later, in equally increased production. It will also be allowed on 

 all hands that soils, already containing enough cinereal food, in 

 the surface-held soluble state, to supply a series of maximum crops, 

 cannot immediately make manifest, and return, in the form of 

 augmented produce, the value of the additional supply received. 

 Such immediate return, it will be agreed, is to be looked for only 

 from soils already exhausted of one or more of their cinereal 

 ingredients ; or if not absolutely exhausted thereof, at least defi- 

 cient of the requisite supplies in the unlocked soluble condition, 

 which alone renders them available for immediate assimilation by 

 plants. Even in this case, moreover, both parties will admit that 

 assimilation cannot take place, and there can consequently be no 

 immediate return, except in so far as all the other conditions 

 (ponderable and imponderable) of plant-growth are simultaneously 

 supplied, — nitrogen among the rest. In mentioning nitrogen, we 

 touch the very centre and throbbing heart of controversy ; one 



