adits were, of course, much fewer, yet pretty numerous. Most of these
were in Manicaland, near Mtali, or to the north and west of Fort
Salisbury, or to the south-east of Gwelo, in the Selukwe district. No
one of these workings was on a large scale, and at two or three only had
stamping machinery been set up, owing, so I was told, to the practically
prohibitive cost of transport from the sea. Accordingly, there were
very few, if any, workings where enough ore had been extracted and
treated to warrant any confident predictions as to the productivity of
the claim. Numerous as the claims are, the value of all, or nearly all,
remained uncertain.

It must be remembered that in these mining districts the gold occurs in
quartz-reefs. Comparatively little is found in alluvial deposits, which
in California and Australia and the Ural mountains have often been more
important than the quartz-reefs. None at all is found diffused equally
through a stratum of rock, as in the Transvaal. Now, quartz-reef mining
is proverbially uncertain. The reefs vary not only in thickness, but
also in depth, and it is not yet certain that any go very far beneath
the surface. So, too, even when the reef itself is persistent in width
and in depth, its auriferous quality varies greatly. What is called the
"shoot" of gold may be rich for some yards, and then become faint or
wholly disappear, perhaps to reappear some yards farther. Thus there
must be a good deal of quartz crushed at different points before it can
be determined what number of pennyweights or ounces to the ton a given
reef, or a given part of a reef, is likely to yield.

In this uncertainty and deficiency of practical tests, people have
fallen back upon the ancient workings as evidence of the abundance of
the precious metal. I have already mentioned how numerous these workings
are over the country, and how fully they appear to confirm the stories
as to the gold which was brought down in the sixteenth and seventeenth
centuries to Sofala and the other Portuguese ports. It is argued that if
gold was so extensively worked in time past by rude races possessing
only primitive methods and few tools, the reefs must have been rich, and
that it is extremely improbable that all, or nearly all, the gold should
have been already extracted. The old workings were open, excavated down
from the surface, and they usually stopped when water was reached. Is
there not every reason to think that in many places th