Mining Ordinances of Spain. 145 



workmen, are poisonous ; and as they drink water incessantly to 

 relieve their exhaustion, they lose the use of their hands and feet, 

 and become bloated. They are subject also to violent pains in the 

 stomach, occasioned by the coldness of the ore.' 



After describing the mode of refining the silver, the author 

 proceeds to describe the operation of cold amalgamation, or 

 amalgamation by the patio, by which the greater part of the 

 gold and silver now circulating over the whole globe has been 

 reduced from the ore. 



' Of the reduction of Ores by Quicksilver. Nature, by exhibiting 

 to mankind the effect of fire in fusing the surface of mountains, 

 first suggested to them the idea of smelting the ores containing 

 lead. Nature also, by setting before them the particles of quick- 

 silver found amongst the ores, first guided them to the method of 

 mixing the harsh ores with quicksilver, salt, and water ; an opera- 

 tion which, although in the infancy of the discovery rude and 

 troublesome in practice, requiring many months to effect the reduc- 

 tion of the gold and silver, has now, by the devices of art, and the 

 lessons of experience (the best instructor in the hidden mysteries of 

 physics), been carried to perfection ; magistral* and various other 

 mixtures being employed, so that the ore may be reduced in twenty 

 days or under and the process has even been completed in twenty, 

 four hours. 



* The object of first importance, in the process of amalgamation, 

 is to provide a skilful amalgamator, capable of distinguishing be- 

 tween smelting ores, and those adapted for amalgamation ; who 

 can make assays, in the small way, to ascertain what the monton 

 will yield in gross ; who understands the proper ingredients, tem- 

 peratures, admixtures, and stirrings to be applied, and who can 

 calculate and compare the probable amount of the expenses and of 

 the metallic produce: for the bringing the silver to the proper 

 point is not to be entrusted to a mere ignorant blockhead. 



4 Secondly, a due selection of the ores must be made, for the 

 purpose, in performing the reduction by amalgamation, of making 

 such mixtures as their nature may require ; and such ores as require 

 smelting, must be set apart for that operation. 



* Third, the ore must be ground as fine as possible, that the 

 quicksilver may combine more readily with the silver. 



* Fourth, the ore being ground, it is the practice, in some dis- 

 tricts, to roast such as is of a sulphureous or bituminous (?) nature, 

 in furnaces adapted for that purpose ; in which the criterion of being 

 sufficiently purified, is the ceasing to give off vapour. The same 

 treatment is also applied to the pyritous or resplendent ores, which, 

 under the influence of fire, lose their splendour, and at the same 

 time, get rid of their prejudicial qualities. Those which contain 



* Sulphuret of copper, roasted and ground to powJer. Trans. 

 VOL. I. OCT. 1830. L 



