“WARNING!
“All trespassers are warned that any attempt to enter this building without invitation from me will cause their instant death. The electrical apparatus cannot be avoided and it strikes with the suddenness of a bolt from heaven.
“The undersigned starts this morning for a distant country and will not return for several weeks. When he does so, the presence or absence of dead bodies in front of this door will inform him whether any one or more or none at all has dared to disregard my notice. It will be equally futile for any one to try to follow me.
“M. Morgan.”
CHAPTER IV.
THE BIPLANE IN ACTION.
HARVEY HAMILTON read the strange “Warning” twice through, by which time every sentence and word were imbedded in his memory. I am glad to say that in one respect he showed common sense: he did not venture a step farther upon forbidden ground. He was tempted to try the door or windows or to explore the premises, but the chances were a hundred to one that Professor Morgan said no more than the simple truth in the pencilled notice tacked upon the oaken door of the cabin.
Possibly it was a violation of that law which forbids a person to use a trap gun in guarding his property against burglars, but if so, the fact itself remained. The person who attempted to force an entrance would undoubtedly run into some infernal contrivance that would instantly blot him out of existence. Consequently, instead of advancing, the youth withdrew several paces where he knew he was safe. He was still near enough to read the ominous words had it been necessary, but he could not forget them.
During the brief while in which he thought upon their meaning, Harvey did a bit of reasoning that would have been a credit to Detective Simmons Pendar himself.