There is a character in Joseph Conrad's "Secret Agent", that of anarchist-arsonist Karl Yundt who, in addition to giving out, by his own account, as much explosive as anyone wants to anyone who wants it (so long as he has just a bit for himself), goes around with a flask of explosive in a coat pocket, connected with a tube winding through shirtsleeves to a small rubber ball in his fist. Describing the arrangement to an associate in a seedy London pub, Yundt complains of the 20-second delay between closing his fist on the ball and triggering the explosive. He boasts about a work-in-progress perfect detonator that would reduce that lag to zero.
"... a detonator that would adjust itself to all conditions of actions, and even to unexpected changes of conditions. A variable and yet perfectly precise mechanism. A really intelligent detonator."