With regard to the process of amalgamation, there seems to be no general rule. The mines vary, not only in the quantity of quicksilver which their ores require, but in the time necessary for the process, and in the loss of quicksilver during the course of it. For instance, the ores of Santa Ana, (a small mine worked by the Administrador of the United Company,) can be reduced by amalgamation in ten days; but with a loss of twenty-five per cent, of quicksilver.
The ores of San Bernabé require sixty days.
Those of La Guitarra and La Magdalena vary from twenty to twenty-eight days, with a loss of only eight per cent. of quicksilver.
The costs of the process may be estimated in the following manner:—
The Tarea requires 30lbs. Quicksilver.
Magistral, thirty Quartillos. (Six to the Arroba.)
Salt from Ăhăhuĭstlăn, fifteen Arrobas, or ordinary Salt, twenty-two Arrobas.
The Mexican amalgamators explain this difference by their favourite terms of Minerales frios, (cold or sluggish Minerals,) and Minerales calientes, (hot ores, easily acted upon,) and they attempt no more scientific solution of the changes which occur. Nor is it probable that any will be given until, by analyzing all the different ores of Mexico, some general principles are established, upon which a theory may hereafter be founded, and improvements successively introduced. I mention these
