twelve o'clock
As soon as he reached the sentinel , he made known his wishes , and ended by offering the man his watch and forty dollars in gold if he would permit himself and his friend to pass the gate at night . At the same time he promised the man he would take all the responsibility in the event of detection or re-capture . The sentinel listened attentively , and at first appeared unwilling to receive the bribe , but upon Harry representing to him that there was no chance of his agency in the escape being discovered , he finally consented to receive it . It was , therefore , arranged between them , that at twelve o'clock that night the two prisoners should start . The signal was to be a faint whistle , which would ultimate to the guard that they were there , if it was answered they should advance , but if not they should return , as his silence would either indicate that he was not alone , or that he was not on his post . Everything having been amicably arranged between them , Harry promised to pay the bribe as soon as they had reached the gate . This the fellow demurred to at first , but as Harry was determined , not to pay over the watch and forty dollars , until the hour of their departure , he was compelled to assent .