four o'clock
`` But if I may I 'll come over to-morrow and play tennis . Will you be at home in the afternoon ? '' `` No , '' she declared promptly , with a mischievous laugh , `` I sha n't . I shall be in the glen by the first bridge at four o'clock , and shall wait for you there . '' `` Very well , I 'll be there , '' he laughed . `` But why should we meet in secret like this , when everybody knows of our engagement ? '' `` Well , because I have a reason , '' she replied in a strained voice -- `` a strong reason . ''