INDUSTRIAL CHEMISTRY—BAEKELAND. 229 
used up so eagerly that the supply lasted only a very few years. In 
the meantime, the ammonium salts recovered from the by-products 
of the gas works have come into steady use as nitrogen fertalizer. 
But here again the supply is entirely insufficient, and during the 
later period our main reliance has been placed on the natural beds 
of sodium nitrate, which are found in the desert regions of Chile. 
This has been, of late, our principal source of nitrogen for agriculture, 
as well as for the many imdustries which require saltpeter or nitric 
acid. 
In 1898 Sir William Crookes, in his memorabie presidential address 
before the British Association for the Advancement of Science, called 
our attention to the threatening fact that, at the mcreasing rate of 
consumption, the nitrate beds of Chile would be exhausted before 
the middle of this century. Here was a warning—an alarm call— 
raised to the human race by one of the deepest scientific thinkers of 
our generation. It meant no more nor less than that before long 
our race would be confronted with nitrogen starvation. In a given 
country, all other conditions being equal, the abundance or the lack 
of nitrogen available for nutrition is a paramount factor in the degree 
of general welfare, or of physical decadence. ‘The less nitrogen there 
is available as foodstuffs, the nearer the population is to starvation. 
The great famines in such nitrogen-deficient countries as India and 
China and Russia are sad examples of nitrogen starvation. 
And yet, nitrogen, as such, is so abundant in nature that it consti- 
tutes four-fifths of the air we breathe. Every square mile of our 
atmosphere contains nitrogen enough to satisfy our total consumption 
for over half a century. However, this nitrogen is unavailable as long 
as we do not find means to make it enter into some suitable chemical 
combination. Moreover, nitrogen was generally considered inactive 
and inert, because it does not enter readily in chemical combination. 
William Crookes’s disquieting message of rapidly approaching 
nitrogen starvation did not cause much worry to politicians—they 
seldom look so far ahead into the future. But to the men of science 
it rang like a reproach to the human race. Here, then, we were in 
possession of an inexhaustible store of nitrogen in the air, and yet, 
unless we found some practical means for tying some of it into a suit- 
able chemical combination we should soon be in a position similar 
to that of a shipwrecked sailor, drifting around on an immense ocean 
of brine, and yet slowly dying for lack of drinking water. 
As a guiding beacon there was, however, that simple experiment, 
carried out in a little glass tube, as far back as 1875, by both Caven- 
dish and Priestley, which showed that if electric sparks were passed 
through air the oxygen thereof was able to burn some of the nitrogen 
and to engender nitrous vapors. 
