potash to be used in the manufacture of gun-powder. It is h 

 used in agriculture as a source of nitrogen, and it is when put t<> 

 this use that we have to deal with it. 



Nitrate of soda is purely and simply a nitrogenous manure. 

 Its nitrogen is in the most valuable form and one most easily 

 assimilated by plants which absorb their nitrogen from the soil in 

 the form of nitric acid. The use of this manure greatly assists the 

 absorbtion of phosphates by plants from the soil. Lawes says that 

 organic matter in the soil is reduced much quicker by nitrates than 

 by ammonia. Nitrate of soda, as a general rule, increases the 

 weight of a crop more than sulphate of ammonia. The crops most 

 benefited by nitrate of soda are the cereals, beet-root, mangolds 

 and potatoes, the leguminous crops only when used in small 

 quantities, as they are able to obtain a large part of the nitrogen 

 necessary for their growth from the atmosphere. Nitrate 

 of soda is sometimes said to be an exhauster of the soil. 

 This is scarcely correct, and the ill-founded assertion has 

 caused a great deal of unjust prejudice against the use of nitrate 

 of soda as a manure. The fact of the matter is that it gives an 

 increased crop. The increase must naturally take more mineral 

 matter out of the soil, but only in the proportion to the increase of 

 crop. For what it takes out it gives a large return, or as Storer puts 

 it, " You cannot eat the cake and have the cake," but if the crop 

 eats the cake it gives you more money to buy more cakes. There 

 is no increase of the per centage of the ash in the crop, as will be 

 shown by the following results of Maercker's on the use of nitrate 

 of soda. 



Nitrate of soda, when pure, contains 16-4 per cent, of nitrogen. 

 It is generally sold with a refraction of 5 per cent, or 95 per cent, of 

 purity, which contains 1575 per cent, of nitrogen, about equal to 

 19 per cent, of ammonia, therefore 125 parts will equal as much as 

 100 parts of ammonium sulphate in ammonia. Xitrate of soda is 

 very soluble and difficult to fix in the soil, so is easily washed out, 

 more especially if there is no crop growing to take it up at once. It 

 gives no results the second year, or at least very little. It 

 is generally applied as a top-dressing at different times, which gives 



