Larry Dubb, aged lly, of Albany, N.Y. for his question:

What Is dust?

We all know how dust settles on the furniture. We can wipe every surface clean and close up a room, A few days later, the tops of tables and bookshelves, the cracks and corners of ehair legs will be covered with a fine film of grey dust. This dust was already in the air of the closed room, As long as there mere drafts, it could float and hang suspended in the air. But it had to fall and settle in the still air.

Sometimes a sunbeam shows up this kind of dust. Tiny bite glow in the sunlight and you can watch, them drifting and floating here and there. This dust comes from the solid things around us, Minute fragments of clothes and furniture are forever wearing away. Tiny bits drift off in the form of dust, Other dust is gathered by the wind outdoors? It comes from soil, rock buildings,  plants and living things.

All this dust is made of fairly large particles .. large enough to see in a, sunbeam. There is also much finer dust present in the air,

Some of this is made of tiny plant spores seeking a place to grow.

Some is pollen dust. Some is made of molecules of salt blown by the sea spray. Some is made of fine ash and smoke.

This fine dust  made of particles far too small to be seen. It drifts on the breezes miles above the earth, It is present everywhere.  It is even in the purest air over the oceans, A thimbleful of air taken from over the ocean might contain 1000 to 4000 particles of this fine dust, A thimbleful, of city air may contain 200,000 particles or more.

Much of this fine dust is fine ash and smoke tossed high by erupting volcanoes, No matter where a volcano erupts, sooner or later its fine dust is carried around the whole world. Other ashy dust comes from beyond our world. Every hour thousands of tiny meteors hit the atmosphere of our earth, We spot a few of them as they burn to bites, We see them shooting stars. The fine ash from these burned out grains of stuff drifts down, down to the earth.

All the time, a fine, fine film of dust is settling over the whole world. The world gains a little weight from it. Sometimes a fierce volcano pours forth an extra dose of dust. For a time this dust may steal some of the heat from the sun before it reaches us. Some experts believe that the long bitter Ice Ages may have been caused by dust from a great many volcanic eruptions.

Dust in the high air also effects the colors of sunlight. It bends the sun's rays to show their true colors. Way back in 1853, the volcano Krakatoa near Java blew its top. For three years after, the whole world had especially beautiful sunrises and sunsets caused by the drifting dust,

Fine fragments of dust have one very important job to do. Some of them, especially salt from sea spray tend to soak up water, They help the fine droplets of a. cloud to get into raindrops. Dust on the furniture may be a nuisance. But without it, the world have no vivid dawns and sunsets. And without dust in the air we should have no raindrops,