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THE MYSTERIOUS DUST DEVIL

                                                     A local whirl of dust, usually not more than a few yards in diameter, in which the particles are swept round and round the centre, and are lifted to considerable heights –sometimes to 2,000 or 3,000 feet above the earth’s surface. It is caused by excessive local heating by the sun in an arid region, a strong convection current being formed. Dust devils usually move over the desert at from 5 to 15 miles per hour, though speeds of over 30 miles per hour are sometimes reached, and as many as five or six of them may often be counted by the observer. Being so limited in size, they are harmless even to aviation.       A storm in which a thick mass of dust obscures the atmosphere, and reduces visibility very considerably –sometimes practically to zero. It causes acute discomfort on the surface, and is a danger to aviation. It is caused by a turbulent wind blowing over an arid, dusty surface, and its approach is usually heralded by

WHAT YOU MUST KNOW ABOUT THE SUN

         The sun; a giant, glowing ball of gas some 850,000 miles in diameter . The temperature at its surface is over 11,000 F ., hot enough to vaporize any material known to man. Deep within the sun, the temperature rises to over twenty million degrees, a heat we cannot begin to imagine or comprehend.             The sun dominates our solar system, containing more than 99% of the system’s matter. The sun is a thousand times as massive as Jupiter, the largest planet, and 335 , 000 times as massive as the earth. And if the sun were hollow, 1,300,000 earths could be fitted inside!            In short, the sun is immense; it is the unquestioned center of the solar system.            And yet, when compared with other stars, the sun is nothing more than average. There are stars a dozen times as massive as the sun, and others but a tenth as large. There are stars that outshine our sun 50,000 times over, and others just a hundredth as bright.             In fact, the sun i