Mining Ordinances of Spain. 143 



as they have been erroneously supposed in this country to be. 

 The processes employed by them, although conducted with 

 little scientific knowledge, and, generally speaking, with no 

 other guide than long practice and experience in the pursuit, 

 are found, from the nature of the ores, and the circumstances 

 of climate and other local accidents, to be better adapted for 

 that country than any others, as is sufficiently proved by the 

 complete failure of Sonneschnied and his colleagues, in their 

 attempt, under the auspices of Charles III., to introduce into 

 America the improvements of Europe*. 



The smelting process is described by the author as fol- 

 lows : 



* Of preparing and mixing the Ores, previous to their reduction by 

 Smelting. Of the construction of the various Smelting Furnaces 

 employed. All the ore raised from the mines is carried to the 

 reduction works, where a receipt is signed on the memorandum 

 brought by the carrier from the mine. The workmen at the reduc- 

 tion works, taught by experience, distinguish the ores adapted for 

 smelting, from those proper for amalgamation, according to their 

 nature, and arrange them separately in an office or store-room. 

 The ore is pounded by beating with a pick or hammer, or more 

 readily, and at less expense, in stamping mills ; and being reduced 

 to fragments of a greater or less size, according to its tractability 

 or obstinacy under the action of the fire, it is piled in heaps, or 

 spread out at once for the purpose of making the revoltura or 

 revolturon, which is the mixing together of several ingredients, 

 namely, the principal ore, the assistant oref, litharge, impregnated 

 cupels or bottoms of furnaces, plomillos^,Jierros^ and slag. 



* In making this mixture, the nature of the ore is attended to ; 

 some ores requiring a mixture of all these ingredients, and others 

 not. No general rule, however, can be given for these mixtures, 

 but the miner must frame rules for his own government, founded 

 on repeated experiments and long observation, making him familiar 

 with the nature of the ore. 



* The mixture, being prepared in the manner above described, is 

 placed in the furnace to be smelted. There are many descriptions 

 of furnaces ; some being made of stone, some of mud bricks, and 



* See Souneschnied's Tratado de la Amalgamation de Nueva Espana; in the 

 preface to which the author acknowledges his inability, after ten years' labour, to 

 introduce with effect, into Mexico, either the process of Baron Born, or any other, 

 prefcr;il>U> to that of the patio, which, he says, in p. 91 of the work, 'has subsisted 

 two centuries and a-half, and will subsist as long as the world endures.' 



f ' Metal de Ayuda' Ore of a more fusible character, mixed with the less 

 tractable ores to assist their fusion. 



J ' Plomillos' Scoriae charged with lead. 



$ Fierros' Slag or scum, being an unreduced mass of oxides and sulphurets, 

 in which those of i/w predominate, 



