Douglas Hast, aged 8, of Fort Bragg, Cal if, for his question:

Is there a black frost?

Yes, indeed. There is a black frost, It is dreaded by farmers, fruit growers and gardeners. For it destroys tender young leaves, buds, blossoms and baby fruit. If it comes, it comes in the spring, when the time for frost should be over.

Sometimes a black frost starts out looking white. In the morning, the world is covered with crisp, icy rime. It is a beautiful sight. Then you remember it is springtime. The new leaves have budded, bravely expecting warm weather.

The spring sun melts the white rime, But the damage is done. New leaves and buds are left wilted and dying. Soon they dry and turn black. This is the blackness of the destructive black frost.

No part of the United States is entirely free from frost.

Last year, tons of Georgia, peaches ‑were destroyed...by late frosts, The Weather Bureau does all it can to help the farmers against these late frosts. And many crops can be saved if the farmers are warned and well prepared.

The Weather Bureau has special fruit‑frost stations in California, Oregon, Washington, Texas and Florida. Reports are made every week. Special bulletins are sent out in emergencies. The citrus growers, especially, can put this information to good use, Many an orange and grapefruit crop has been saved from a black frost because the farmer was ready to fight it‑,

He had ready lots of small heaters. They were all primed with diesel oil. The farmer had them placed on the ground among his precious trees. Maybe he had as many as 60 stoves to an acre of fruit trees. The little stoves gave off a lot of heat, but not much smoke.

The frost begins when the temperature drops to 32 degrees Fahrenheit: At that point, the water vapor in the air chills from a gas to fragments of ice. This is what make the white rain. If there is little or no vapor in the air, the frost is just as dangerous to the trees. It freezes the moisture in the new buds and leaves, This makes a black frost without first being white,

But the farmer's little stoves can prevent the damage. They need only to raise the temperature a few degrees, They win the fight if they can keep the temperature above 32 degrees Fahrenheit. That is the danger point at which water vapor turns to rime and the moisture in the leaves turns to ice. And sixty of those little stoves to an acre can raise the temperature twelve degrees around the orchard trees,