On the Chemical Properties of Soils. 
117 
wliicli 1 liavc! published some filtration experiments in Part 1., 
vol. XX. of this Journal. For the latter experiments I used liquid 
manure, which, in addition to a great number of chemical fer- 
tilizing matters, contained only 3"3() grains of ammonia in the 
imperial gallon. It might certainly have been expected that 
iO,000 grains of soil would have absorbed this small quantity 
of ammonia, the absorption even tlien being only at the rate of 
•1G8 grains of ammonia to lOOO grains of soil. Notwithstanding 
the large quantity of clay in Mr. Mechi's soil, and the small 
quantitv of ammcmia in his liquid manure, only 1"81 grains of 
ammonia were absorbed by 20,000 grains of soil, and 1*55 grains 
remained in the liquid after three days' contact with it. In this 
experiment 1000 grains of soil thus absorbed only "0905 of a 
grain of ammonia. 
In my remarks on this experiment, I express the opinion that 
a stronger solution of ammonia passed through Mr. Mechi's soil 
would have parted with a much larger proportion of ammonia 
than in this experiment. The proof of this is now given. In 
the former experiment 1000 grains of this clay soil removed only 
•0905 of a grain of ammonia from a very dilute ammoniacal 
liquid ; in the present experiment the same quantity of the 
same soil absorbed about eight times as much, or "754 grains 
of ammonia from the stronger solution, containing 23"24 grains, 
of ammonia per gallon. 
It must, however, be remembered, that whereas I employed in 
my former experiments highly complex liquids, in my present 
trials simple solutions of caustic ammonia were used. The 
([uantity of ammonia which a soil is capable of absorbing must 
no doubt depend in some degree on the conditions under Avhich 
the ammonia is present in the liquid. The preceding experiment 
is, therefore, not quite conclusive. In order to satisfy myself 
beyond doubt whether more ammonia is really removed from a 
stronger than from a weaker solution or not, I instituted a second 
series of experiments, which I must briefly describe. 
Second Series of Absorption Experiments with stronger 
Amjionia Solutions. 
A solution of ammonia in distilled water was prepared, con- 
taining about twice as much ammonia as that used in the first 
series. To speak more exactly, this stronger solution contained 
47'11 grains of ammonia per gallon, or "673 grains of ammonia in 
1000 grains of liquid. 
The clear ammoniacal solution having been poured off the soil 
as completely as was possible in each of the five experiments of 
the first series, the liquid remaining with the soils in the bottles 
