Waste, 
381 
1883.J 
unlimited. The atmosphere, the waters, and the soils have 
all been carefully analysed to determine their proportion of 
this constituent, but everywhere it has been found in very 
small quantities — mere traces. Thus, according to Frese- 
nius, one million parts of air contain as an average only 
0*133 part of ammonia. So that, roughly speaking, seven 
million pounds of atmospheric air contain 1 pound of am- 
monia. The combined nitrogen present in rain-water ranges 
from 8 to 65 parts in ten million parts. Again, not merely 
is the existing store of combined nitrogen thus very small, 
but we find hitherto no efficient provision for its increase or 
renewal. It was formerly believed that plants — some plants 
at least, such as clover, lucerne, peas, and beans — had the 
power of seizing the gaseous nitrogen of the air, and con- 
verting it in their tissues into ammonia, nitrates, or into 
organic compounds. Careful series of experiments, carried 
on in many cases in the hope that this might be true, have 
given, however, a uniformly negative answer. If we plant 
seeds in soil free from combined nitrogen, and pass over 
them only such air as has been carefully deprived of ammo- 
nia or nitric acid, we find in the dwarfed diminutive shoots 
which spring up no more combined nitrogen than pre- 
existed in the seed. A repetition of such experiments, 
under every variation of circumstances, has driven both 
scientific chemists and practical agriculturists to the con- 
clusion that plants cannot assimilate or feed upon the free 
nitrogen of the air. As for animals, they have not even 
the least pretensions to the power which we find plants do 
not possess. 
Nor have we been able to trace in the inorganic world any 
processes which meet the difficulty. Even the small pro- 
portion of ammonia found in the air is certainly in part — - 
and we do not know in how great part — derived from the 
decomposition of animal and vegetable matter. We know 
that nitrogen can be made to combine with oxygen by elec- 
tric sparks, or in other words by lightning. It has also been 
ascertained that the so-called effluve, or silent electric dis- 
charge, can induce the combination of nitrogen with hydro- 
gen, thus forming ammonia. But these processes are 
exceedingly slow and little productive. It has lately been 
established that at great elevations in the atmosphere they 
are even less active than near the earth’s surface. Thus 
water obtained from snow collected at high elevations in the 
Alps contains, according to M. Boussingault, no nitric acid, 
and in some cases no ammonia, the maximum proportion of 
the latter, at heights exceeding 3000 metres, being 1 part in 
ten millions. 
