The object changed from ball shape to saucer shape and flew at a steady altidute and at speed.When I saw the object first, it was ball shaped. It changed from ball shape to saucer shape repeatedly as it moved through the air. The object seemed to keep to the same altitude. When I saw the object the second time, it was flying faster. It was flying at tree-top height and again seemed to keep to the same atlitude - just going higher or changing direction quiclyl to avoid the trees. The object stayed the same colour - black. When I saw it first, it flew west to east. The second time (which was only a few minutes after the first sighting) the object flew south to north. The weather on the evening was dull and overcast - still daylight.