Depiction: A large group of protestors are forced to scatter as a National Guard helicopter flies over the Berkeley campus releasing gas. The photo is an arial one, looking down on large section of campus. AP caption on the photo reads: Helicopter spews tear gas on Sproul Plaza as students gaze upwards yesterday during demonstations at University California Berkeley. Police warned students before chopper descended with its load of irritating gas. Moments later, the plaza was empty expect for National Guardsmen.