paragraph:  Late on the next Sunday afternoon Gifford had gone for a country walk which he had arranged to bring him round in time for the evening service at the little village church of Wynford standing just outside the park boundary.  His way took him by well-remembered field-paths which, although towards the end of his walk darkness had set in, he had no difficulty in tracing.  The last field he crossed brought him to a by-road joining the highway which ran through Wynford, the junction being about a quarter of a mile from the church.  As he neared the stile which admitted to the road he saw, on the other side of the hedge and showing just above it, the head of a man.  At the sound of his footsteps the man quickly turned, and, as for a moment the fitful moonlight caught his face, Gifford was sure he recognized Gervase Henshaw.  But he took no notice and kept on his way to the stile, which he crossed and gained the road.  As he did so he glanced back.  A horse and trap was waiting there with Henshaw in it.  He was now bending down, probably with the object of concealing his identity, and had moved on a few paces farther down the road. 
answer: Because he went out late on Sunday afternoon