feet and
under eight feet, the distance across the vein or lode is usually
divided into two samples. If still wider, each is confined to a
span of about four feet, not only for the reason given above, but
because the more numerous the samples, the greater the accuracy.
Thus, in a deposit twenty feet wide it may be taken as a good guide
that a test section across the ore-body should be divided into
five parts.

As to the physical details of sample taking, every engineer has
his own methods and safeguards against fraud and error. In a large
organization of which the writer had for some years the direction,
and where sampling of mines was constantly in progress on an extensive
scale, not only in contemplation of purchase, but where it was also
systematically conducted in operating mines for working data, he
adopted the above general lines and required the following details.

A fresh face of ore is first broken and then a trench cut about
five inches wide and two inches deep. This trench is cut with a
hammer and moil, or, where compressed air is available and the
rock hard, a small air-drill of the hammer type is used. The spoil
from the trench forms the sample, and it is broken down upon a
large canvas cloth. Afterwards it is crushed so that all pieces
will pass a half-inch screen, mixed and quartered, thus reducing the
weight to half. Whether it is again crushed and quartered depends
upon what the conditions are as to assaying. If convenient to assay
office, as on a going mine, the whole of the crushing and quartering
work can be done at that office, where there are usually suitable
mechanical appliances. If the samples must be taken a long distance,
the bulk for transport can be reduced by finer breaking and repeated
quartering, until there remain only a few ounces.

PRECAUTIONS AGAINST FRAUD.--Much has been written about the precautions
to be taken against fraud in cases of valuations for purchase. The
best safeguards are an alert eye and a strong right arm. However,
certain small details help. A large leather bag, arranged to lock
after the order of a mail sack, into which samples can be put
underground and which is never unfastened except by responsible
men, not only aids security but relieves the mind. A few samples
of country rock form a good check, and notes as to the probable
value of the ore, from inspection when sampling, are useful. A
great help in examination is to have the assays or analyses done
coincid