Miscellanies. 377 



to have been lost, for although resinous, it burns without flame. 

 From personal examination of the country, east of the sandstone ele- 

 vations, Mr. Blake concludes that a lake of considerable extent once 

 covered the space between these and the Cordilleras. Numerous vol- 

 canic rents now exist among the mountains, and it is probable that 

 the saline matter produced by them was dissolved in the water, form- 

 ing a lake at the base of the mountains. This lake subsequently 

 broke its barriers, and prostrated a forest then growing where the 

 saline matter is now found. I have carefully examined the earthy 

 matter which is mixed with the nitrate of soda from different parts 

 of the province of Tarapaca, and find that the larger part is com- 

 posed of fragments of finely powdered shells, the color being un- 

 changed. A brown marl forms the remainder, such as results from 

 the washings of sandstone, — these facts I consider as supporting the 

 conclusion of Mr. Blake. The surface of the pampa is mostly sand, 

 clay, and saline matter. The latter is composed of sulphate of lime 

 and soda, salt, and nitrate of soda — some parts present the nitrate of 

 soda at the surface — at others, a few feet below. These salts have 

 all the physical and chemical characters of sails produced by decom- 

 position and separated by evaporation from solutions. The nitrate of 

 soda is found in distinct strata, a thin layer of brown loam separating 

 the parts ; it is also found mixed with salt, and forming a small por- 

 tion of the whole mass. The refining operations are rude and simple. 

 The richest masses of the native salt are blasted or broken and divi- 

 ded into small portions ; with these, copper kettles are in part filled, 

 and water, or the mother water of former operations, is added, and 

 heat applied until a boiling and saturated solution is obtained. The 

 solution is transferred to wooden coolers, where the nitrate of soda 

 crystallizes. The undissolved salt remaining in the kettles is thrown 

 aside, fresh salt being used each time, although not one half of the 

 nitrate of soda is dissolved. The coolers are emptied after the crys- 

 tals of nitrate have ceased to form ; it is dried, packed in bags, and 

 sent to the coast on mules. The wood used in the operations is 

 transported from a distance on the backs of mules from the borders 

 of the pampa. Of late, attention has been turned to using the alter- 

 ed wood of the buried forest, and some excavations promised a sup- 

 ply. Water is found by sinking wells in some places, below the sa- 

 line soil. The subsistence of the workmen, drivers and mules, is 

 mostly drawn from Valparaiso. The quantity of nitrate of soda 

 which exists in beds is immense, and in addition it is probable that 

 the saline soil would afford a large supply. 



Native nitrate of soda, in fractured masses, has a granular struc- 

 ture, arising from the aggregation of irregular rhombic crystals, va- 



