ms to which he was occasionally subject, there had been reason
to believe that his secret would escape him, and every precaution had
been taken to note his slightest utterance. But Thomas Roch had
each time disappointed his watchers. If he no longer preserved the
sentiment of self-preservation, he at least knew how to preserve the
secret of his discovery.

Pavilion No. 17 was situated in the middle of a garden that was
surrounded by hedges, and here Roch was accustomed to take exercise
under the surveillance of his guardian. This guardian lived in the
same pavilion, slept in the same room with him, and kept constant
watch upon him, never leaving him for an hour. He hung upon
the lightest words uttered by the patient in the course of his
hallucinations, which generally occurred in the intermediary state
between sleeping and waking--watched and listened while he dreamed.

This guardian was known as Gaydon. Shortly after the sequestration of
Thomas Roch, having learned that an attendant speaking French fluently
was wanted, he had applied at Healthful House for the place, and had
been engaged to look after the new inmate.

In reality the alleged Gaydon was a French engineer named Simon Hart,
who for several years past had been connected with a manufactory of
chemical products in New Jersey. Simon Hart was forty years of age.
His high forehead was furrowed with the wrinkle that denoted the
thinker, and his resolute bearing denoted energy combined with
tenacity. Extremely well versed in the various questions relating to
the perfecting of modern armaments, Hart knew everything that had been
invented in the shape of explosives, of which there were over eleven
hundred at that time, and was fully able to appreciate such a man
as Thomas Roch. He firmly believed in the power of the latter's
fulgurator, and had no doubt whatever that the inventor had conceived
an engine that was capable of revolutionizing the condition of both
offensive and defensive warfare on land and sea. He was aware that the
demon of insanity had respected the man of science, and that in Roch's
partially diseased brain the flame of genius still burned brightly.
Then it occurred to him that if, during Roch's crises, his secret was
revealed, this invention of a Frenchman would be seized upon by some
other country to the detriment of France. Impelled by a spirit of
patriotism, he made up his mind to offer himself as Thomas Roch's
guardian, by passing himself of