FUNCTIONS OF SODIUM NITRATE 297 



It was found that the average composition of 104 samples 

 of caliche, taken from as many different claims, was 9.54 per cent, 

 of niter. The quantity of niter which has been located in South- 

 ern California is difficult to estimate. The following estimate 

 comprises the whole amount of niter which is thought to exist 

 in the small areas surveyed, but it does not indicate what can 

 be commercially extracted. About 35,000 acres of the deposit 

 have been examined, in which it is estimated that there exist 

 about 22,000,000 tons of nitrate of soda. This, of course, is only 

 a very rough estimate and is perhaps of little value in basing 

 computations of the future supply. 



In general, it may be said that the niter beds of California are 

 at the present time of little importance from a commercial point 

 of view. Not only is the amount of niter comparatively small, 

 but the distance from markets and the cost of transportation 

 are so great as to practically exclude the product from the mar- 

 kets of the world. 



It is stated by Pennock that no commercial success has at- 

 tended the exploitation of nitrate deposits in the United States. 61 

 According to the same author the production of nitrate of soda 

 is practically confined to Chile. 



260. Functions of Sodium Nitrate. Practically the only form 

 of oxidized nitrogen which is of importance from an agronomic 

 point of view is sodium nitrate, often known in commerce by 

 the name Chile saltpeter. Ammoniacal compounds and nitrites 

 are usually oxidized to nitric acid or its compounds before they 

 are assimilated as plant foods. Applied to a growing crop, sodium 

 nitrate at once becomes dissolved at the first rainfall or by the 

 natural moisture of the soil. It carries thus to the rootlets of 

 ' Journal of the American Chemical Society, 1906, 28 : 1248. 



