MODERN HIGH FARMING. 85 



its attack by the carbonic acid and render its subsequent solu- 

 bility a work of comparative ease. 



In lands which contain an abundant or even a moderate supply 

 of lime, there can, consequently, be no doubt as to the rapid de- 

 composition of the acid phosphates, and the assimilation of their 

 phosphoric acid. But where both difficulty and danger may be en- 

 countered is when an absence or deficiency of lime characterizes the 

 soil. For in such cases, not only will the phosphoric acid remain 

 unassimilable, but the excess of free sulphuric acid may exercise a 

 corrosive action on the roots, or combine with the oxides of iron to 

 form sulphate, the baneful properties of which we have dwelt upon 

 elsewhere. 



The arguments in favor of soil analysis, constituted by these 

 considerations, appear to us to be conclusive, and they will not fail 

 to add their weight to our oft-repeated assertion, that to know 

 what elements to apply and in what form to apply them, we must 

 first of all possess perfect information on the physical and chemical 

 properties of the lands under treatment. Do they lack phosphoric 

 acid, and have they plenty of lime ? Then superphosphates are the 

 natural prescription. But if they are shown to lack a sufficiency of 

 both phosphoric acid and lime, they must either be well limed first, 

 and afterwards receive the superphosphates, or we must devise some 

 other form, in which the two necessary matters may be simultaneous- 

 ly plowed in, with the prospect of obtaining speedy and beneficial 

 results. 



We have already striven to impress our readers with the belief 

 that the origin of manures, or the form in which they present the 

 needful constituents, are both utterly insignificant, providing those 

 constituents be of a nature to become at once available for the crops. 

 We shall therefore be understood when we say that our own ten- 

 dencies, based upon long experience and experiments, are in favor, 

 wherever it is possible, of substituting the use of precipitated phos- 

 phates for the acid supers. 



Precipitated phosphates are obtained by dissolving the raw and 

 finely powdered phosphatic material in muriatic acid, which, when 



