engineers led them further afield, as told in "_The Young Engineers in
Arizona_." A great, man-killing quicksand had to be filled in and
effectively stopped from shifting. Reade & Hazelton undertook the task.
Incidentally Tom came into serious, dangerous conflict with gamblers and
other human birds-of-prey, who had heretofore fattened on the earnings of
the railway laborers. It was a tremendously exciting time that the young
engineers had in Arizona, but they at last got away with their lives and
were at the same time immensely successful in their undertaking.

In "_The Young Engineers In Nevada_" we found our young friends under
changed conditions. While at work in Colorado and in Arizona Tom and
Harry had studied the occurrence of precious ores, and also the methods
of assaying and extracting ores. Having their time wholly to themselves
after finishing in Arizona the dauntless young pair went to Nevada, there
to study mining at first hand. In time they located a mining claim, though
there were other claimants, and around this latter fact hung an extremely
exciting story. Both young engineers nearly lost their lives in Nevada,
and met with many strenuous situations. Their sole idea in pushing their
mine forward to success was that the money so earned would enable them to
further their greatest ambition; they longed to have their own engineering
offices. In the end, their mine, which the young engineers had named "The
Ambition," proved a success. Thereupon they left their mining partner, Jim
Ferrers, in charge and went east to open their offices.

We next found the young engineers engaged to the south of the United States
border. These adventures were fully set forth in the preceding volume in
this series, entitled "_The Young Engineers in Mexico_." Tom and Harry,
engaged to solve some problems in a great Mexican mine, found themselves
the intended tools of a pair of mine swindlers of wealth and influence.
From their first realization of the swindle Tom and Harry, even in the face