But the action was hydrothermal,
just such as was seen in course of operation in New Zealand a few years
ago when, in the Rotomahana district, one could actually see the growing
of the marvellous White and Pink Terraces formed by the release of
silica from the boiling water exuding from the hot springs, which water,
so soon as the heat and pressure were removed, began to deposit its
silica very rapidly; while at the Thames Gold-field, in the same country
hot, silicated water continuously boiled out of the walls of some of
the lodes after the quartz had been removed and re-deposited a siliceous
sinter thereon.

On this subject I note the recently published opinions of Professor
Lobley, a gentleman whose scientific reputation entitles his utterances
to respect, but who, when he contends that gold is not found in the
products of volcanic action is, I venture to think, arguing from
insufficient premises. Certainly his theories do not hold good either in
Australasia or America where gold is often, nay, more usually, found at,
or near, either present or past regions of volcanic action.

It is always gratifying to have one's theories confirmed by men whose
opinions carry weight in the scientific world. About seventeen years ago
I first published certain theories on gold deposition, which, even then,
were held by many practical men, and some scientists, to be open to
question. Of late years, however, the theory of gold occurrence by
deposition from mineral salts has been accepted by all but the "mining
experts" who infest and afflict the gold mining camps of the world.
These opine that gold ought to occur in "pockets" only (meaning thereby
their own).

Recently Professor Joseph Le Conte, at a meeting of the American
Institute of Mining Engineers, criticised a notable essay on the
"Genesis of Ore Deposits," by Bergrath F. Posepny. The Professor's
general conclusions are:

1. "Ore deposits, using the term in its widest sense, may take place
from any kinds of waters, but especially from alkaline solutions, for
these are the natural solvents of metallic sulphides, and metallic
sulphides are usually the original form of such deposits."

2. "They may take place from waters at any temperature and any pressure,
but mainly from those at high temperature and under heavy pressure,
because, on account of their great solvent power, such waters are
heavily freighted with metals."

3. "The depositing waters may be moving in any direct