Walcott Held for Manslaughter..Boston, Oct. 29.—“Joe” Walcott, the negro pugilist, was held for the grand jury Friday in $2,500 onacharge of manslaughter in connection with the death of another negro, Nelson Hall, recently. The pugilist’s revolver is said to hays been accidentally discharged and a ball which first went through one of Walcott's hands, badly injuring it, entered Hall’s breast, causing almost instant death.