of this story, while Dick Donovan's researches in natural history
provided the boys with a lot of fun.

The volume immediately preceding this showed the boys coming to the
rescue of a poor lad, a waif and orphan, who yet had a fortune in the
plans and specifications of a new type of craft invented by his dead
father who had lacked the capital to develop it. Enemies strove
desperately to secure the papers, and even went to the length of
forging a will for the purpose, but partly through the agency of an
odd German lad, Heiney Pumpernickel Dill, their schemes were
frustrated and the invention was developed and set upon a working
basis. This book was called the Boy Inventors' Hydroaëroplane, and
dealt with some astonishing adventures and perils all of which the
boys encountered with plucky spirits and resourceful minds.

For some weeks preceding the opening of the present book relating of
the Boy Inventors, Mr. Chadwick had been closeted in his own private
laboratory. The boys had seen him only at rare intervals, and then he
had appeared abstracted and preoccupied. This, the boys knew, was a
sure sign that he was at work on a new idea.

Sometimes the lights burned in his laboratory far into the night and
in the morning he would appear at breakfast pale and silent. The boys
had indulged in much speculation as to what the new invention could
be, but had arrived at no satisfactory conclusion when, two days after
their experience with the eccentric professor, Mr. Chadwick summoned
them to his private workshop. The boys, who had been at work on the
Wondership, the flying automobile with which they had met such
surprising adventures in Brazil, obeyed the summons with alacrity. It
was delivered to them by Jupe, the negro factotum of the place.