oxidation, doing by controlled natural means, in about two minutes or
less, what natural means uncontrolled would take ages to do.  Many virgin
gold districts are worked where the ore has been oxidised slowly through
long periods by the oxygen of the atmosphere.  The process of the
extraction of the gold from the disintegrated ore is commonly that known
as "amalgamation" with mercury.  Mr Hutchinson's plan, adopted by the Gold
Ores Reduction Company, is to rapidly oxidise the ore by supplying air at
a high temperature.  The ore is first crushed by a Blake stone-breaker, in
this case of the Morris form.  Then it is ground by an apparatus like a
"mortar mill" into fine powder.  Then comes the step of the invention.
There is a highly-heated brick flue, some 10 feet high, with slanting
shelves in it.  The pulverised ore is sifted in at the top; it slides from
shelf to shelf in the heated atmosphere, absorbs the oxygen, and reaches
the bottom with the slate, antimony, arsenic, or whatever other
environment there be, oxidised.  This does the atmospheric work of
countless centuries.  The remainder of the work, the mixing with mercury,
washing away the oxidised products, and the separation of the gold from
the mercury in a retort, are much on old plans, though mechanically
improved.