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, (JZenneberg’s Journal, 1864, 
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 indifference. 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 *|,,,, 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, ( Vs. S¢., 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: 
2 i i 2.10 
Lime - - - - - - 15.10 
Magnesia - = - - - 1.50 
Phosphoric acid - - - - 0.16 
Sulphuric acid) - - - = 7.50 
Mianeacid - - = - «= 6.00 
Silica, Chlorine, Oxide of iron - - traces 
0 | 
Water - - - - - - - - 99,967.64 
100,000 — 
Nobbe, (Vs S¢., VIII, 337,) found that in a solution con- 
taining but ’*|,,,,, of solid matters, which was continually 
