The Evil Shepherd by E. Phillips Oppenheim

It was a day when chance was kind to Francis. After leaving his rooms at the Temple, he made a call at one of the great clubs in Pall Mall, to enquire as to the whereabouts of a friend. On his way back towards the Sheridan, he came face to face with Margaret Hilditch, issuing from the doors of one of the great steamship companies. For a moment he almost failed to recognise her. She reminded him more of the woman of the tea-shop. Her costume, neat and correct though it was, was studiously unobtrusive. Her motoring veil, too, was obviously worn to assist her in escaping notice.

She, too, came to a standstill at seeing him. Her first ejaculations betrayed a surprise which bordered on consternation. Then Francis, with a sudden inspiration, pointed to the long envelope which she was carrying in her hand.