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SCIENCE 



[N. S. Vol. XL. No. 102a 



than it is supplied to the soil through 

 natural agencies. "We have tried to remedy 

 this discrepancy by enriching the soil with 

 manure or other fertilizers, but this has 

 been found totally insufficient, especially 

 with our methods of intensive culture — our 

 fields want more nitrogen. So agriculture 

 has been looking anxiously around to find 

 new sources of nitrogen fertilizer. For a 

 short time, an excellent supply was found 

 in the guano deposits of Peru; but this 

 material was used up so eagerly that the 

 supply lasted only a very few years. In 

 the meantime, the ammonium salts recov- 

 ered from the by-products of the gas-works 

 have come into steady use as nitrogen 

 fertilizer. 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 industries which require salt- 

 peter or nitric acid. 



In 1898, Sir William Crookes, in his 

 memorable presidential address before the 

 British Association for the Advancement 

 of Science, called our attention to the 

 threatening fact that, at the increasing 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 con- 

 fronted 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 food-stuffs, the nearer 

 the population is to starvation. The great 



famines in such nitrogen-deficient countries 

 as India and China and Kussia are sad 

 examples of nitrogen starvation. 



And yet, nitrogen, as such, is so abun- 

 dant in nature that it constitutes four fifths 

 of the air we breathe. Every square mile 

 of our atmosphere contains nitrogen enough 

 to satisfy our total present consumption 

 &r 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 inex- 

 haustible store of nitrogen in the air, and 

 yet, unless we found some practical means 

 for tying some of it into a suitable chem- 

 ical 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 1785, by 

 both Cavendish and Priestley, which 

 showed that if electric sparks were passed 

 through air, the oxygen thereof was able 

 to bum some of the nitrogen and to en- 

 gender nitrous vapors. 



This seemingly unimportant laboratory 

 curiosity, so long dormant in the text-books, 

 was made a starting point by Charles S. 

 Bradley and D. E. Lovejoy, in Niagara 

 Falls, for creating the first industrial ap- 

 paratus for converting the nitrogen of the 



