22 TOBACCO. 



or artificial. The fertilizer acts on the soil, and the soil 

 reacts on the fertilizer ; but the point we wish to make 

 prominent is this, that diiferent soils are differently 

 affected by one and the same application, or in other 

 words, a given manure fertilizes a given crop unequally in 

 degree, and unlike in kind, on different soils, by virtue of 

 the different assimilating or fixing power, which the soil 

 exerts upon its ingredients. 



" We know of the existence of these peculiarities of soils, 

 and something of their causes and of the laws by which 

 they act ; but the real necessities of the tobacco crop, or 

 of any other crop, as respects soil-ingredients, cannot be 

 arrived at by chemical analysis of a single sample, nor of 

 a dozen samples." Thus analyses of a dozen New 

 England tobaccos showed the following highest and 

 lowest percentages of each ash-ingredient, and of 

 nitrogen ; — 



" It appears that the percentages of nitrogen, phosphoric 

 acid and potash are nearly twice as great in some samples 

 as in others ; that the proportions of magnesia and lime 

 are about 2^ times greater in some samples than in others, 

 and that sulphuric acid is 3 times more in one case than in 

 another. The variation of silica is still greater, and the 

 disparity rises to its extreme in case of soda and chlorine, 

 whose maxima are respectively 20 and 30 times greater 

 than their minima." 



