MANUFACTURE OF NITRATK OF SODA. 283 



about 3 cwt. each when full, and loaded on the railway cars, which 

 are run on to the drying-floors by a siding in each floor, one 

 hundred sacks being carried in each car. It then goes to Iquique 

 by rail, and is exported to Europe and the United States as the 

 well-known fertilizer and article of commerce, nitrate of soda. 



The cost of machinery, plant, and construction of these 

 works amounted to £110,000. The whole was finished and was 

 producing nitrate on the 23rd of Maj', 1884, or in the short space 

 of six months after the arrival of the first lot of machinery. The 

 celerity with which the machinery was placed in a state of com- 

 plete efiiciency is partly due to the choice of good mechanics and 

 artizans brought out by the Author from England, and to the 

 firms who stippliod the machinery, and esj)ecially to the able 

 assistance rendered by the manager and resident engineer, Mr. 

 James Anderson. The disadvantages of working in a desert 60 

 miles from a town considerably increased the difficulties of 

 constructing these works. 



There is but one oficina on this coast with more boiler-power 

 than Eamirez, namely that of Antofagasta, designed and con- 

 structed by Mr. .1. F. Spencer, M. Inst. C.E., assist-.-d by the late 

 Mr. J. Gr. Ada mson, Assoc. M. Iifst. C.E.; and it is probably the 

 finest piece of plant engineering in South America; but it has never 

 produced more than 4,500 tons of nitrate per month, owing to the 

 very low grade of caliche belonging to the works, the average 

 now only containing 20 per cent, of nitrate, the remainder being 

 salt and insolubles The refuse thrown out from Eamirez tanks 

 contains only 3 per cent, of nitrate. This could be extracted 

 by more washing, but it would cause a superfluity of weak wash- 

 ings and a reduction in the strength of mother-liquor, so as to 

 need further evaporation in order to reduce the volume and raise 

 the density. During the past six months the ratio of nitrate pro- 

 duced to coal consumed was as 12 to 1; or for every ton of coal 

 burnt, no less than 12 tons of nitrate of soda were manufactured. 



One of the most serious questions in the nitrate districts is 

 the supply of water, The water found in wells in the Pampa 

 collects in hard cavities by constant percolation from the melted 

 snow on the Andes or Cordilleras. The course of this water is, 

 however, very irregular ; and there are some oficinas which have 



