As a last test, he dropped to a level of three thousand feet, at which time they were considerably north of Albany, and throwing the automatic-pilot into operation calmly removed his hands and feet from every control except the rudder.  In this fashion they ran for fifteen or twenty miles on a perfectly even keel, the apparatus automatically working the elevators and ailerons of the craft as various wind currents tended to disturb its equilibrium.  At length, John gave a little twist to the rudder, and the way the Sky-Bird began to circle, and to bank of her own accord, was a splendid sight to behold.  No hawk, sailing over a barnyard in quest of an unwary fowl, could have performed the trick more beautifully.