THE ASH OF PLANTS. 171 



of ammonium is employed to supply maize "with nitrogen, 

 this salt is decomposed, its ammonia assimilated, and its 

 chlorine, which the plant cannot use, accumulates in the 

 solution in the form of chlorhydric acid, to such an extent 

 as to prove fatal to the plant, {Henneberg^s Journal, 18G4, 

 pp. 116 and 135.) Such disturbances are avoided by 

 employing large volumes of solution, and by frequently 

 renewing them. 



The concentration of the solution of is by no means a 

 matter of indifiference. While certain aquatic plants, as 

 sea-weeds, are naturally adapted to strong saline solutions, 

 agricultural land-plants rarely succeed well in water-cul- 

 ture, when the liquid contains more than " |,j„„ of solid mat- 

 ters, and will thrive in considerably weaker solutions. 



Simple well-water is often rich enough in plant-food to 

 nourish vegetation perfectly, provided it be renewed suf- 

 ficiently often. Sachs' earliest experiments were made with 

 well-water. 



Birner and Lucanus, in 1864, ( Ys. St., VIII, 154,) raised 

 oat-plants in well-water, which in respect to entire weight 

 were more than half as heavy as plants that grew simul- 

 taneously in garden soil, and, as regards seed-production, 

 fully equalled the latter. The well-water employed, con- 

 tained in 100.000 parts : 



Potash 2.10 



Lime 15.10 



Magnesia ----- 1.50 

 Phosphoric acid - - - - 0.16 

 Sulphuric acid - . - - 7.50 



Nitric acid 6.00 



SUica, Chlorine, Oxide of iron - - traces 



Solid Matters 32.36 



Water 99,967.64 



100,000 

 Nobbe, ( Vs. St., VIII, 337,) found that in a solution con- 

 taining but ' |j„|,„„ of solid matters, which was continually 



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