572 Professor George Lunge [March 15, 



out a little more than half a century ago, when the exploitation of 

 the beds of nitrate of soda in South America was begun. The crude 

 nitrate found there is refined on the spot, and comes to us as " Chilian 

 saltpetre," whicli is almost pure sodium nitrate, to the tune of a 

 million and a half tons per annum. About four-fifths of this is 

 taken up bj agriculture, the remainder serving, in the first place, for 

 the preparation of nitric acid. As for that acid, it is impossible to 

 imagine how we could do without it. Apart from minor, but quite 

 indispensable uses, one of which is in the manufacture of sulphuric 

 acid by the lead-chamber process, the greater part of nitric acid is 

 consumed in the manufacture of coal-tar colours and in that of 

 explosives. 



Let us pause for a minute to consider the last-named. Even 

 supposing it possible that all wars could be abolished on this terres- 

 trial globe — a contingency not very likely to arise within the next few 

 years, in spite of the laudable efforts of the Peace Societies — and that 

 gunpowder were no longer required for shooting wild animals (an 

 equally unlikely case, which would lead to a quite intolerable increase 

 of game, big and otherwise) — we cannot conceive the possibility of 

 our present system of civilisation enduring without a colossal con- 

 sumption of explosives. How could we carry on mining operations 

 without them ? How could we get stones from the quarries ? 

 How could we construct roads, and tunnels, and railways without the 

 help of explosives, all of which have a basis of salts or esters of nitric 

 acid ? And these have, up to the present, been prepared almost 

 exclusively from Chilian saltpetre. The idea has certainly been 

 mooted to imitate the natural process by which the nitrate is formed 

 in India. This has been tried during a number of years in France and 

 in Sweden, but has been given up as unprofitable in our northern 

 climes. Also, the interesting experiment of sowing the bacillus of 

 nitrification and of cultivating it in the soil has proved a failure, 

 although I would fain believe that the last word has not been spoken 

 on that subject. This, if successful, would replace some of the nitrate 

 now used as fertiliser, just as a better utilisation of sewage would 

 act in the same direction ; but all this at the best goes only a very 

 small way, and does not furnish the pure saltpetre required for the 

 manufacture of nitric acid. What, then, shall we do when the nitre 

 beds of Chili are exhausted ? an event which, according to most 

 estimates, is bound to take place within thirty or forty years from noAV. 

 Unfortunately, there is no tangible hope of similar beds being found 

 in any other localities, certainly not to any great extent. The beds 

 of Atacama and Tarapaca on the Cordillera owe their origin to an 

 altogether exceptional combination of climatic conditionsand geological 

 changes, the repetition of Avhich in other quarters is exceedingly un- 

 likely. Until very few years ago there was no prospect of any fresh 

 supplies of nitrates in any other direction ; but we may say that the 

 solution of this problem, if not altogether settled in its final shape, has 



