o the
world's gold supply. These drifts which are auriferous from grass roots
to bed rock extend for nearly fifty miles, and are in places over 200
feet deep. Want of capital and want of knowledge has hitherto prevented
their being profitably worked on a large scale.

The extraction of reef gold from its matrix is a much more complicated
process, and the problem how most effectively to obtain that great
desideratum--a complete separating and saving operation--is one which
taxes the skill and evokes the ingenuity of scientific men all over the
world. The difficulty is that as scarcely any two gangues, or matrixes,
are exactly alike, the treatment which is found most effective on
one mine will often not answer in another. Much also depends on the
proportion of gold to the ton of rock under treatment, as the most
scientific and perfect processes of lixiviation hitherto adopted will
not pay, even when all other conditions are favourable, if the amount of
gold is much under half an ounce to the ton and even then will leave
but a very small profit. If, however, the gold is "free," and the lode
large, a very few pennyweights (or "dollars," as the Americans say) to
the ton will pay handsomely. The mode of extraction longest in vogue,
and after all the cheapest and most effective, for free milling ores
where the gold is not too fine, is amalgamation with mercury, which
metal has a strong affinity for gold, silver, and copper.

As to crushing appliances, I shall not say much. "Their name is legion
for they are many," and the same may be said of concentrators. It may
be old-fashioned, but I admit my predilection is still in favour of
the stamper-battery, for the reason that though it may be slower in
proportion to the power employed, it is simple and not liable to get out
of order, a great advantage when one has so often to depend on men who
bring to their work a supply principally of main strength and stupidity.
For the same reason I prefer the old draw and lift, and plunger pumps to
newer but more complicated water-lifters.

On both these points, however, I am constrained to admit that my opinion
has recently been somewhat shaken.

I have lately seen two appliances which appear to mark a new era in the
scientific progress of mining. One is the "Griffin Mill," the other the
"Lemichel Siphon Elevateur."

The first is in some respects on the principle of the Huntingdon Mill.
The latter, if the inventor may be believed and the