If there should be much base metal in your sample such as say stibnite (sulphide of antimony), a most troublesome combination to the amalgamator—­instead of the formula mentioned above add to your mercury about one dwt. of zinc shavings or clippings, and to your water sufficient sulphuric acid to bring it to about the strength of vinegar (weaker, if anything, not stronger), place your material preferably in an earthenware or enamelled basin if procurable, but iron will do, and intimately mix by stirring and shaking till all particles have had an opportunity to combine with the mercury.  Retort as before described.  This device is my own invention.

The only genuine test after all is the battery, and that, owing to various causes, is often by no means satisfactory.  First, there is a strong, almost unconquerable temptation to select the stone, thus making the testing of a few tons give an unduly high average; but more often the trouble is the other way.  The stuff is sent to be treated at some inefficient battery with worn-out boxes, shaky foundations, and uneven tables, sometimes with the plates not half amalgamated, or coated with impurities, the whole concern superintended by a man who knows as little about the treatment of auriferous quartz by the amalgamating or any other processes as a dingo does of the differential calculus.  Result:  3 dwt. to the ton in the retort, 30 dwt. in the tailings, and a payable claim declared a “duffer.”

When the lode is really rich, particularly if it be carrying coarse gold, and owing to rough country, or distance, a good battery is not available, excellent results in a small way may be obtained by the somewhat laborious, but simple, process of “dollying.”  A dolly is a one man power single stamp battery, or rather an extra sized pestle and mortar (see “Rules of Thumb").

Silver lodes and lodes which frequently carry more or less gold, are often found beneath the dark ironstone “blows,” composed of conglomerates held together by ferric and manganic oxides; or, where the ore is galena, the surface indications will frequently be a whitish limey track sometimes extending for miles, and nodules or “slugs” of that ore will generally be found on the surface from place to place.  Most silver ores are easily recognisable, and readily tested by means of the blowpipe or simple fire assay.  Sometimes the silver on being tested is found to contain a considerable percentage of gold as in the great Comstock lode in Nevada.  Ore from the big Broken Hill silver load, New South Wales, also contains an appreciable quantity of the more precious metal.  A natural alloy of gold containing 20 per cent silver, termed electrum, is the lowest grade of the noble metal.

Tin, lode, and stream, or alluvial, occurs only as an oxide, termed cassiterite, and yet you can well appreciate the compliment one Cornish miner pays to another whose cleverness he wishes to commend, when he says of him, “Aw, he do know tin,” when you look at a representative collection of tin ores.  In various shapes, from sharp-edged crystals to mammillary-shaped nuggets of wood-tin; from masses of 30 lbs. weight to a fine sand, like gunpowder, in colour black, brown, grey, yellow, red, ruby, white, and sometimes a mingling of several colours, it does require much judgment to know tin.