midnight
`` An impenetrable mystery '' was sure `` to hang for ever '' as far as all mankind was concerned . But what of that if he alone of all men could never get rid of the cursed knowledge ? And Comrade Ossipon 's knowledge was as precise as the newspaper man could make it -- up to the very threshold of the `` _ mystery destined to hang for ever _ ... '' Comrade Ossipon was well informed . He knew what the gangway man of the steamer had seen : `` A lady in a black dress and a black veil , wandering at midnight alongside , on the quay . ` Are you going by the boat , ma'am , ' he had asked her encouragingly . ` This way . ' She seemed not to know what to do .