158 
Economy of Nitrogen . 
[April, 
equivalent of 34 per cent of potash, and, according to our 
estimate of 100 million lbs. as the world’s total annual 
production, about 34 million lbs. of this valuable body are 
thus withdrawn from the immediate service of agriculture. 
But the potash is not, like the nitrogen, withdrawn from 
utility. When a battle takes place all the potash contained 
in the gunpowder exploded gradually settles down upon the 
earth in the form of a fine dust, and, being washed into the 
soil by the next shower, becomes again available for the 
food of crops, and shares with the “ red rain ” the honour 
of making the harvest grow ! 
The other explosives in practical use — such as gun-cotton, 
nitro-glycerin in its manifold disguises and modifications, 
fulminate of mercury, &c. — all share with gunpowder the 
cardinal fault of unlocking combined nitrogen and returning 
it as an inert gas to the atmosphere. Wheresoever, there- 
fore, man works by dint of explosions he is warring against 
life itself. The glorious victories of the warrior, the triumphs 
— often little less costly — of the civil engineer, the very “set 
pieces ” of the pyrotechnist, the red fire in which the villain 
of the stage meets his retributive fate, and the squibs and 
crackers which have now for some two centuries been an- 
nually blazed away in honour of Guy Fawkes, are all 
bought at the cost of potential life, and all tend to make life 
more difficult. 
We have now seen two of the great forms of the waste of 
combined nitrogen : wasted, as far as the excreta of man 
and animals are concerned, partly by conveyance into rivers 
and seas, partly by destructive fermentation, and in case of 
the explosives by a reduction differing from destructive fer- 
mentation merely in its more rapid character. But for both 
these kinds of waste there is at any rate the apology to be 
advanced that the nitrogen brought into play was essential. 
In other words, combined nitrogen is absolutely indispensable 
in the food of man and animals, and if their excreta are 
subsequently misapplied, and not returned to the soil, that 
does not condemn the original use of the nitrogenous matter. 
In the explosives, again, the nitrogen is not an inert con- 
stituent, but in the cases we have taken is essential. We 
cannot make either gunpowder, gun-cotton, nitro-glycerin, 
or picric acid without oxidised nitrogen, though we may and 
should most earnestly seek to produce explosives available 
for praCbical use which shall not require this expenditure of 
one of the main elements of life. 
But there is another form of the waste of nitrogen more 
unjustifiable still. In pointing out some instances of this 
