504 
The Iiijliiencc of Lime on the 
came to .a state of dilution, involving a comparatively slow 
absorption. Indeed the difficulty of removing tlie last portions 
of lime was so great, that I devised an experiment to see whether 
that point was ever reached, — whether the entire causticity of 
lime-water could be removed by any quantity of soil. 
Experiment No. 16. 
3000 grains of the soil No. 16 were digested with 10,000 
grains of lime-water (1449), and the mixture was left to digest, 
with continual agitation, for 1 hour; at the end of that time it 
still contained caustic liine. An addition of 840 grains of soil 
was now made ; the liquid still remained caustic. A further 
addition of 1000 grains of soil was now made, and the liquid 
when tested was found to be free from caustic lime. It ap])ears, 
therefore, that the causticity of lime can be entirely neutralized 
by a soil, if sufficient of the latter is employed. In this case it 
required altogether 4840 grains of soil to remove, within a 
moderate time, 14 49 grains of lime contained in 10,000 grains 
of lime-water ; so that each 1000 grains of soil combined only 
with about 3 grains of lime, whereas from the same solution 
when in excess we have seen 1000 grains of the same soil to 
absorb as much as 15 grains of lime, or five times as much. It 
appears very much ns if this was only a question of time, and 
that soils would ultimately take up the same quantity of lime, 
whether from a weak or a strong solution. 
The fact may, however, have in some cases a practical bearing 
of considerable importance, as an excessive dressing with lime 
would be very long before it lost its causticity in the soil, and, 
for aught we know, until this point is reached, the water in 
the soil being continually charged with lime in the caustic state, 
a soil may be totally unfit for tlie production of crops. In this 
t^ircumstance we may by possibility, therefore, find an explana- 
tion of the well-established fact, that an excessive dose of lime 
does, on some soils, produce serious and lasting mischief. I 
merely, however, throw this out as a suggestion, without attach- 
ing too much weight to it. The main object of these lime 
experiments was not so much to determine the quantity of the 
alkali which the different soils would take up as to ascertain 
what influence it would have on their power of absorbing 
ammonia. 
I have already stated that it was supposed that lime, by con- 
verting double silicates of soda, which were themselves vmable to 
absorb ammonia from the air, into corresponding salts of lime 
which stnmgly possess that power, might put the soil in a better 
state for the acquisition of atmospheric ammonia. To test this 
