106 FORESTRY OF NORWAY. 
inorganic constituents out of the air and distilled water; 
and there were superficial experiments which seemed to 
countenance the idea. Subsequently the error lay in the 
other extreme, for there was manifested a disposition to 
ascribe a peculiar flora to each geognostic formation. 
‘The truth seems to lie between the two extremes. 
‘Whenwe find that the ashes of tobacco, of clover, of lucerne, 
contain more than 20 per cent. of lime and magnesia salts, 
we cannot be surprised if we do not meet with them on 
pure sandy soils containing scarcely a trace of lime; but-it 
would be drawing a false conclusion from this to say that 
the musselkalk, or the -keuper limestone, or the Jura 
limestone, or. any other calcareous stratum of any given 
formation is exactly the proper soil for these plants. 
‘That a plant like the great sugar tangle (Laminaria 
saccharina), which is so rich in soda, iodine, and bromine, 
occurs only in the sea, and not in fresh water, where soda 
is very sparingly, and iodine and bromine not at all 
present, is certainly easily conceivable. But it is certain, 
at the same, time, when we decide upon the soils on a 
large scale, according to geognostic principles, that there 
are very few plants characteristic of particular constituents, 
and this relation is, indeed, neither very natural nor neces- 
sary. In the next place it may be asserted that all plants 
contain the same constituents in their ashes, but in very 
different proportions. 
‘On a soil, therefore, composed purely of one kind of 
earth—eg., lime, silex, or gypsum—no plant at all could’ 
flourish. Every soil that bears plants contains also in its 
composition all the substances required by all plants, only 
the proportions differ, and the predominance of silex, lime, 
or common salt, must consequently favour especially the 
growth of grasses, pulses, or other plants, although these 
are by no means exclusively confined to the proper sandy 
or calcareous soils, or to the sea-side. In reference to this 
point,’ says Schleiden, ‘I know really no other plants than 
the carbonate of lime plants, the gypsum and salt, plants, 
which I could bring forward in evidence. 
