They were advised not to go into the mines, as the descent must be made by ladders which are not constructed like ordinary ones, but are nothing more than logs set upright and notched alternately on opposite sides. The miners ascend and descend very nimbly along these rude ladders, and accidents are rare; but strangers find them dangerous.
Frank and Fred were quite willing to take the risk, but the Doctor was more prudent, and suggested that they would defer their visit to the interior of a mine until they reached one with less liability to mishap. But this did not interfere with a visit to one of the reduction-works, for which a permit was readily obtained.
FIELD WITH ADOBE WALLS.
"Before we make the visit," said the Doctor, "I want you to learn what the patio process of reduction is, so that you can see intelligently. The patio process is in use here, as it is throughout Mexico and South America generally."
In the hour they had at their disposal, Frank and Fred informed themselves on the subject, and were able to write as follows:
