Show Volcanic Ash The average e volcanic eruption does docs not make the upper air dusty but when the outbreak takes take the theof form of a violent explosion great quantities of ot fine min mineral r ll dust so- so called ash reaches much higher levels than are ever attained by wind lifted soil or by the soot from tom fires In the strong winds prevailing prevail prevail- ing at such levels the dust soon spreads out In an enormous canopy canopy cano py dense enough to produce a nurr ber of striking effects |