84 SS. W. Johnson on some points of Agricultural Science. 
pound silicates, or the adhesive force of water, (solvent action) 
for the saline bodies, may neutralize or limit the chemical affinity 
which determines one compound and give origin to another. 
Hence the chemical substitutions in the soil, and in the case of 
rootlets of plants upon the mrs an action which thougt exceed- 
ingly obscure and as Prof. Liebig remarks in enunciating his 
Ww views hig esiecians to form a conception of,” we may 
eiwit in some ¢ 
Liebig in his pavine on modern pate en p- 48, gives this 
instance : ‘We frequently find in meadows smooth ‘lime-stones 
8. 
that the rootlets have acted upon the stone, but are not therefore 
necessarily compelled to assume that the dissolved matters have 
entered the plant or were dissolved as food, for in such lime- 
soils the excess rather than the deficiency of carbonate of lime is 
oftener a hindrance to — In the case of the Lycopodi- 
acece, which contain alum mpare quantity combined with 
or came from s a an a 
x But it is evident from the facts that have been. adduced that 
t is unnecessary to have urse to any new —s to explain 
ecu that ik between se = silicates, sesquioxyds and 
saline solutions may take place in the soil; but in addition to 
these a number of other changes must go on there, as the soil is 
so complex and variable a mixture. The organic matters (the 
bodies of the humic acid group), which are often though not 
abree pence in no erencereDie quantity in the water extract 
e soils, can y fail to exert an influence to modify 
the MOG Ei Ihave found that a peat (swamp- 
