A Philosophical and Practical Essay on the Gold and Silver Mines of Mexico and Peru (Paperback)

This historic book may have numerous typos, missing text or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1755. Not illustrated. Excerpt: ... a Sponge does Water, so that it is incorporated in it, and separated from the Earth, Lead, and Copper naturally mixed with it; then they go about to part it from all that Dross, and to separate it from the Quicksilver also, which is n .lo; done after this Manner. They How the Sit- . * n * ver is extras- throw the Ore into great Cisterns ed from tht of Water, where it is moved about Mercury." with a Sort of small Water-Mills or Wheels, after the Manner of dissolving or grinding of Mustard; and thus all the earthy Part goes off with the running Water, and the Silver and Mercury being heaviest settles at the Bottom of the Cistern. The Metal, so left behind, is like Sand, which is taken thence and carried to be washed again in Troughs or Trays at certain great Pools of Water, where all the rest of the Earth goes off, leaving behind the Silver and Mercury, though some little of the Two last always goes over with the Clay, which is called the Relaves, or Washings; and even that they afterwards endeavour to save. When the Silver and Mercury are quite clean and shining, being cleared from all the Earth and Dross, they take that Metal, and putting it into a Linnen Cloth, squeeze it very hard, which fetches out all the Mercury that is not incorporated with the Silver; and the rest remains in a Mass or Body of Silver . and Mercury, like the Paste of Almonds when the Milk of them is pressed out; and when that Mass or Body is well squeezed, only the Sixth Part os it is Silver, and the other Five Parts arc Mercury; so that if the Mass or Cake weighs Sixty Pounds, Ten Pounds thereof are Silver, and the other Fifty Mercury. These Masses are afterwards made up like Sugarloaves, hollow within, and each of them generally Weighing an Hundred Weight. To separate the Mercury f...