I carry in my pocket. It's the principle of the pneumatic instantaneous
shutter for a camera lens. The tube leads up--"

With a swift disclosing gesture he gave Ossipon a glimpse of an india-
rubber tube, resembling a slender brown worm, issuing from the armhole of
his waistcoat and plunging into the inner breast pocket of his jacket.
His clothes, of a nondescript brown mixture, were threadbare and marked
with stains, dusty in the folds, with ragged button-holes. "The
detonator is partly mechanical, partly chemical," he explained, with
casual condescension.

"It is instantaneous, of course?" murmured Ossipon, with a slight
shudder.

"Far from it," confessed the other, with a reluctance which seemed to
twist his mouth dolorously. "A full twenty seconds must elapse from the
moment I press the ball till the explosion takes place."

"Phew!" whistled Ossipon, completely appalled. "Twenty seconds! Horrors!
You mean to say that you could face that? I should go crazy--"

"Wouldn't matter if you did. Of course, it's the weak point of this
special system, which is only for my own use. The worst is that the
manner of exploding is always the weak point with us. I am trying to
invent a detonator that would adjust itself to all conditions of action,
and even to unexpected changes of conditions. A variable and yet
perfectly precise mechanism. A really intelligent detonator."

"Twenty seconds," muttered Ossipon again. "Ough! And then--"