312 HOW CROPS TEED. 



Tlie foregoing analyses (all the author has access to 

 that are sufficiently detailed for the purj^ose) indicate 



1. That the quantity of soluble matters is greatest— 400 

 to 1,400 in 100,000— in wet, peaty soils (X, XI, XIII), 

 though their aqueous solutions are not rich in some of the 

 most important kinds of plant-food, as, for example, phos« 

 phoric acid. 



2. That poor, sandy soils (VIII, XII) yield to water the 

 least amount of soluble matters,— 40 to 45 in 100,000, 



3. That very rich soils, and rich soils especially when 

 recently and heavily manured as for the hop and beet 

 crops (I, II, V, VI, VII, IX, XIV, XV, XVI), yield, in 

 general, to water, a larger proportion of soluble matters 

 than poor soils, the quantity ranging in the instances be- 

 fore us from 50 to 150 parts in 100,000. 



4. It is seen that in most cases phosphoric acid is not 

 present in the aqueous extract in quantity sufficient to be 

 estimated; in some instances other substances, as mag- 

 nesia, chlorine, and sulphuric acid, occur in traces only. 



5. In a num.ber of cases essential elements of ])lant- 

 food, viz., phosphoric acid and sulphuric acid, are wanting, 

 or their j^resence was overlooked by the analyst. 



Composition of Drain-Water.— Before further discus- 

 sion of the above data, additional evidence as to the kind 

 and extent of aqueous action on the soil will be adduced. 

 The water of rains, falling on the soil and slowly sinking 

 through it, forms solutions on the grand scale, the study 

 of which must be instructive. Such solutions are easily 

 gathered in their full strength from the tiles of thorough- 

 drained fields, when, after a period of dry weather, a rain- 

 fall occuis, sufficient to saturate the ground. 



Dr. E. Wolff, at Moeckern. Saxony, made two analyses 

 of the A\ater collected in the middle of May from newly 

 \aid tiles, when, after a period of no flow, the tiles had 



