He Could Stop the World by Kenneth Robeson

BEFORE Johnny could turn or reply, he was enveloped in the shrouding folds of a black cloth. No doubt, the mild Professor Randolph knew something of the geologist's prowess.

Johnny's bony, elongated figure doubled and straightened. Both his knuckled fists found instant marks. Though he could not see, the geologist sensed the presence of half a dozen misguided persons who possibly had imagined he would be easily overpowered.