Name that movie----with a surveyor

Richard Pryor enters an old west town in a wagon with a tripod with mounted instrument standing in the middle of the wagon. He begins to set up in the middle of the main street and does a terrible job of pretending to survey something with a few chaining pins and a plumb bob on a string that requires continuous movement similar to a pendulum. He looks through the scope in one direction then later looks through the scope from the opposite end. The townspeople stand around watching in awe.