Chapter 10

Amount of exports 332 Date of discovery of nitrate deposits 333 The origin of nitrate deposits 334 Forbes and Darwin on the theory of their origin 335 Source of nitric acid in nitrate of soda 337 Guano theory of origin of nitrate of soda 337 Nitric acid in nitrate of soda probably derived from sea-weed 339 Appearance of nitrate-fields 340 The method of mining the nitrate of soda 341 Composition of _caliche_ 342 Extent of the nitrate deposits 342 Composition and properties of nitrate of soda 343 Nitrate applied as a top-dressing 344 Nitrate of soda encourages deep roots 344 Is nitrate of soda an exhausting manure? 345 Crops for which nitrate of soda is suited 346 Method of application of nitrate of soda 347 Importance of having a sufficiency of other fertilising constituents 348 Conclusions drawn 349

APPENDIX TO CHAPTER IX.

Total shipments from South America, 1830-1893 351 Total imports into Europe and United Kingdom, 1873-1892 351