half past nine
With an effort , recovering , she sought to distract the girl . `` Surely you must see now , you have got to go ! There 's a boat to the mainland at six thirty . If you catch that , you 'll have three hours ' start ; for the detective wo n't be able to get off the island before half past nine . And you ought to be able to lose yourself in that time somehow . Hurry ; I 'll help you pack a satchel . You 'd better wear that blue serge ; everybody wears blue serge , so it 's inconspicuous .