midnight
Bob and Frank , joint owners of the airplane , grinned at each other . `` Well , fellows , '' said Jack , `` We have got to sleep . So I propose that we stand guard turn about tonight . It 's pretty late now , midnight or thereabouts , so that if we stand two hour watches , the three of us , we 'll pull through nicely without spoiling Mr. Temple 's slumber . '' The older man protested he was as able to stand a watch as any of them , but the boys would n't have it so . Finally it was agreed that Jack should take the first watch of two hours , Bob would succeed him and Frank would have the last watch . The man keeping watch would sit inside his bedroom door opening on to the gallery , with Jack 's revolver .