The daily morning journal and courier., 1898-11-28


 Continue grinding the ore till it is in the form of powder. This powder is heaped into cone, which is divided into four parts, of which the sampler takes two whose angles are opposite to one another. Mix these two parts thor oughly and again divide into four; take two portions again,a and so on till sam pie of convenient bulk yielded is, on any ordinary calculation of probability, certain to represent accurately the or iginal mass taken.
 certain quality of this sample is now weighed out, two equal amounts being taken as checks upon each other. The weighing may be done in denomina- tional values of either grammes or as- say tons The assay ton is most con- venient invention, and is very simply explained The ordinary ton contains 32,6666 ounces: if, then, we make unit Gan assay ton) weighing S2,6667 grammes, each oO1 of a gramme will equal one ounce per ton. Thus. no call culation, is needed at all to estimate the gold richness of an ore per ton.
 Say we weigh out, then, two separate portions of the ore of one assay ton GA. ID each With each mix thoroughly bicarbonate of soda, litharge, borax, glass, and flour in varying proportions; when thoroughly uniform In color, emp ty the mixtures in fireclay crucibles, and strew on the top thin layer of salt Put on the lids of the two cruei- bles and surround them with living coal coke, or burning vaporized benzo- line in crucible furnace. The cruci- bles are heated till the masses of ore and fluxes are in a state of tranquil fusion that is, not bubbIing or boiling The white-hot fluid is then poured into iron moulds and allowed to cool. On examination, after cooling, the fused masses will be found to consist of: CD
 layer of white substance, which is salt, (2) A slag. This is usually dark in col or, often resembling malachite, and is formed by the fusion of the borax and soda with the worthless or earthly mat ter (grangue) in the ore. (3) A lead button, produced from the litharge, or lead oxide, originally mixed in the charge. This lead button contains all the silver and gold in the ore. The heat of the furnace drives off from the lead oxide it's oxygen, so that pure lead is left; this, in virtue of it's weight, per- colates downward through the slag dur ing the heating in the furnace, collect ing all the gold and silver present, and eventually forms a button weighing, if a proper amount of flour has been add ed originally, about sixteen to twenty grammes. The flour has the effect of varying the size of lead button produc- ed, and is said to posses a reducing &C., tion.
 The next step in the process is to get rid of the lead without also losing the gold and silver. This is done by an op- eration known as cupellation. The cupel IS small, round, bone-ash cup, which is placed in sort of fireclay tunnel with one end closed up, known as a muffle. The muff1e is heated from the outside, either by burying it with coals or by playing buring gas on every part of it. When the cupel has attained the heat of the interior of the muffie, the lead button is placed in it and the door of the muffle shut, so as to procure the greatest amount of heat possible. When the lead is seen to be melted and fum- ing, the muffie door is opened to admit the air, which is sucked i'll by the in- tense heat.
 The oxygen contained in the air oxy- dizes the lead into lead oxide, and the bone-ash cupel absorbs lead oxide like a sponge, but refuses to absorb the gold and silver; so that at length there is left in the cupel only a button of the two precious metals It is to be suppos- ed that two ore samples have been treated similarly both in the crucibles and cuDels: but for the sake, of con- venience, it is better to explain the treatment of one only. The bead of gold and silver obtained weighs, let us say, .0016 of a gramme. This is noted down. The bead after weighing is flattened out in a fiatting- mill, so as to expose as large a surface as possible to the nitric acid which is then added to it. On heating, the silver is dissolved, but, of course, the gold is untouched by the action of any single acid. The remain ing pure gold is treated with stronger acid, called parting acid" to drive off any suspected trace of silver, and then washed with water. If the part ing of the gold from the silver has