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320 A. LIVERSIDGE. 
mammillated, and it is on that account that to the unassisted — 
eye, the gold has a dull brown or ochre colour. 
The preceding experiments are not numbered because they are 
merely qualitative ones, but the next series of experiments were 
quantitative; weighed pieces of pure sheet gold were put up with 
various organic reducing substances; sulphides and other naturally 
occurring substances which I thought might form a galvanic 
couple, and which would throw down the gold from solution upon 
the plate as in the electroplating process. 
A.— With a Gold Nucleus and Organic Matter. 
In the following experiments, pure gold specially prepared 
by the late Dr. Leibius, Senior Assayer of the Sydney Mint, and 
assaying 1000 was rolled out into fillets of $5 inch thick, so as 
to expose a large surface and yet be strong enough to handle, these 
were heated in a cornet crucible to burn off impurities and then 
boiled with nitric acid, and well washed to get rid of any sulphur 
or other contaminations from the gas flame. The nuggets and 
specimens of native gold used as nuclei were also cleaned in the | 
same way. ‘The fillets were next weighed and placed in stoppered 
glass cylinders with a solution of the sodium chloraurate, supplied 
for photographic purposes, and made up of the usual strength of 
a fifteen grain tube of the salt to fifteen ounces of water. 
The reducing substances were similar to those used by Wilkinson, 
but as will be seen with results just the reverse of what he obtained, 
i.e., the gold foil or other nucleus weighed less instead of more ' 
after the experiments. 
Experiment 1—A water worn nugget was used as a nucleus 
the dust of the air was allowed to fall in, and the experiment 
was continued for one hundred and sixty-eight days, with an 
occasional addition of gold solution as the liquid in the cylinder 
became colourless from the reduction of the gold. Although a 
good deal of gold was precipitated on and around the nugget none 
of it was adherent, and on reweighing it was found to have lost 
002 gramme. 
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