es, I have found in them what I believe to be gold existing as a
natural sulphide. The lode is a large irregular one of pure arsenical
pyrites carrying, in addition to gold and silver, nickel and cobalt. It
exists in a felsite dyke immediately on the coast. Surrounding it on all
sides are micaceous schists, and in the neighbourhood about half a mile
distant is a large granite hill about 800 feet high. In the lode and its
walls are large quantities of pyro-phyllite, and in some parts of the
mine there are deposits of pure white translucent mica, but in the ore
itself it is a yellow or pale olive green, and is never absent from the
pyrites.

"From the first I was much struck with the exceedingly fine state of
division in which the gold existed in the ore. After roasting and very
carefully grinding down in an agate mortar, I have never been able to
get any pieces of gold exceeding one-thousandth of an inch in diameter,
and the greater quantity is very much finer than this. Careful
dissolving of the pyrites and gangue so as to leave the gold intact
failed to find it in any larger diameter. As this was a very unusual
experience in investigations on many other kinds of pyrites, I was led
further into the matter.

"Ultimately, after a number of experiments, there was nothing left but
to test for gold existing as a natural sulphide. Taking 200 gr. of ore
from a sample assaying 17 oz. fine gold per ton, grinding it finely and
heating for some hours with yellow sodium sulphide--on decomposing the
filtrate and treating for gold I got a result at the rate of 12 oz. per
ton. This was repeated several times with the same result.

"This sample came from the lode at the 140 ft. level, whilst samples
from the higher levels where the ore is more oxidised, although carrying
the gold in exactly the same degree of fineness, do not give as high a
percentage of auric sulphide.

"It would appear that all the gold in the pyrites (and I have never
found any gold existing apart from the pyrites) has originally taken its
place there as a sulphide."

Professor Newbery, who made many valuable suggestions on the subject,
says, speaking of gold in pyritous lodes:

"As it (the gold salt) may have been in the same solution that
deposited the pyrites, which probably contained its iron in the form of
proto-carbonate with sulphates, it was not easy at first to imagine any
ordinary salt of gold; but this I find can be accomplished with very
dilute so