Stanley G. Weinbaum 
The Black Flame [EPUB ebook] 

Thomas Marshall Connor was about to die. The droning voice of the prison chaplain gradually dulled his perception instead of stimulating his mind. Everything was hazy and indistinct to the condemned man. He was going to the electric chair in just ten minutes to pay the supreme penalty because he had accidentally killed a man with his bare fists.
Connor, vibrantly alive, vigorous and healthy, only twenty-six, a brilliant young engineer, was going to die. And, knowing, he did not care. But there was nothing at all nebulous about the gray stone and cold iron bars of the death cell. There was nothing uncertain about the split down his trouser leg and the shaven spot on his head.