The San Francisco Examiner from San Francisco, California • 67

1 1 II 0 IK IO, It II I I I Ml )) I I hi yu? it i Hi '7 Ly It twi ii iv Ii i 1 .1 I 1 1 ,1 If i 1 itf'O- WOC vtffti.g tt trA6 tttaKW, im .1 11 in. mil I im mu iHiiM.n inn i Wi nJ UKr 1" 4 A Fertile American Mieat Field and a Slice of tlie Barren Desert of Sahara Placed Alongside of It Nature's Threat Unless the Farmers Turn the Land Back to a Protective Covering of Grass, The Rich Corn and Wheat Lands of the Middle-West May Become Almost as Barren as the Great Deserts of the World, Agricultural Experts Warn, Unless the Farmers Turn Some of Their Fields Back to Grass IgplNOT FERTILE LACKINGK if i SKiCWER JABLE3ffli? 1 if if--5 EpWATER LOGGED SOlLigr BE LOW VATE.R LF-VELt'-; Volcanoes Are Great Dust Producers, as This View of the Eruption of One of Java's Forty-Nine Volcanoes Reveals. A Typical Section of Farm Soil in the Western Plains Region Showing How the Loss of Turf Exposes Fertile Top Soil to Wind and Rain, Leaving Only the Subsoil. Which Contains No Humus or Vegetable Matter, and Therefore Is Sterile, in which pinkish water, supposedly tinged with blood, was seen to fall from the skies, collect in basins and so on. Actual bloodstains were said to be left on white clothing, white buildings and so on exposed to the rain.

For many centuries these events were accepted by everyone as portents, sent by one or an the rain washed over it there was no disturbance of the soil. But farmers have driven out the cattlemen who grazed their stock on the grass, and have ploughed up the land to sow It to wheat, corn and other crops. Thus nature's protection of, the A Rcnuirkable Picture of a ''Haboob," Otherwise Known as a Sandstorm, From the Sahara Desert Near Khartoum, Egypt. Dust Breathed in During the Average Day by a Resident of New York Is Said to Equal Nearly a Teaspoonful. During the Recent Storm This Dust Consumption Was Increased Many Times.

Doctors Do Not Yet Know Just What Effect It May Have on Health. scientists of the Texas Technological College to be gigantic generators of electricity, so that dusty days undoubtedly cause important changes in the electrification of the air. Dust in the air changes the color of the sky, st that many dust storms one after an other might turn the earth's skies gre;" instead of the admired celestial blue. One German meteorologist, Dr. Franz Linke, has suggested that the earth's skies actually have become greyer and less blue in the last few decades, as a result of gradual increase of dust in the air, partly because of continual discharge of dust and smoke from factories and partly because the world's climate has become slightly drier in desert regions so that dust storms are becoming more common.

For many years physicians have known that breathing much dust into the lungs may cause serious health damage, even amounting to conditions resembling pneumonia or tuberculosis of the lungs. Recently extensive and careful tests of these dust effects have been made in several laboratories, notably by Dr. Leroy U. Gardner and his associates at the Saranac Laboratory for the Study of Tuberculosis at Saranac Lake, New York and by Professor W. R.

Jones of the Imperial College of Science, near London, England. Both Dr. Gardner and Professor Jones come to the same remarkable conclusion, which is that the important item in the effects of dust on health is the kind of dust that is breathed. In some mines, the dust produced when ore or rock are cut down and blasted contains large amounts of fine particles of the mineral called silica or quartz. This silica dust is found to be extremely injurious.

Unfortunately, the dust of North American dust storms contains a large proportion of the silica minerafs which seem to belong to the group of dusts most harmful in the lungs. That is why the dust of these American storms is grey or yellow, instead of red like the blood-rain dusts of Southern Europe. This blood-rain dust, although so much feared by superstitious people because of its color, really belongj chiefly to the iron-ore class, which Dr. Gardner believes is relatively harmless. Whether the recent dust storm sprinkled citizens of the Eastern parts of the country with enough silica dust to do actual harm when breathed is far from certain.

Since the dusty part of the storm lasted only for a few hours, the total number of dust particles breathed by the average individual probably was not great. Public health experts propose, however, to study the numbers of deaths, the cases of lung and throat disease and so on in the affected parts of the United States during the few days or weeks after the dust storm, to see whether any clear and immediate health effects of the dusty air can be discerned. NOBODY who lived in the wide area of the recent astonishing dust storm which moved halfway acros8 the United States will be likely to ever forget it. During the second week of May over a billion tons of dust were picked up by the wind from the parched, drought-ridden plains of Nebraska, the Dakotas and western Canada, and were blown eastward for more than a thousand miles in a gigantic storm which sprinkled and blanketed every part of the country between the plains and the Atlantic Ocean. It took more than six hours for this great mass of powdered earth to pass New York City and hundreds of miles out at sea the runaway soil of Nebraska fell on ocean steamships.

Nearly three miles up in the air aviators still found traces of this freak of Millions of tons of it were dropped along the way, so that housewives in New York and other Eastern cities swept up and put into their dust bins thousands of tons of Western soil. At one time during the storm air samples taken in New York City showed about forty tons of dust particles suspended in each cubic mile of air, or more than three million pounds of it held suspended 'over the city at a single instant. More of what geologists call translocation of earthy materials was accomplished in a single week than some great rivers manage in many years. Western farms were denuded of millions of dollars' worth of fertile soil, some of which was contributed to Eastern farming regions but more of which undoubtedly was carried out to sea or washed into rivers and thus lost forever to farmers of the present geologic age. It is probable that millions of people received doses of dust breathed into their lungs which will create health troubles for them later on.

How many deaths, during the storm or afterward, should be charged against this unusual convulsion of Nature, science may never be able to determine. But the most startling results of all are pointed out in a warning from the United States Department of Agriculture that a great American desert may be in process of being made throughout "the Middle-West While the dust storm came as a new and surprising phenomenon of nature in the eastern States, yet it is not new in the Middle-West. In hundreds of miles of the region, where great corn and wheat crops have been raised, these dust storms have been frequent. Still more trouble has been caused by soil wash or erosion due to rain water. Nature covered this region with grass, and when the wind blew over it or soil has been removed by the plow, and the winds and rains have been steadily carrying away the fertile top-soil.

The Department of Agriculture experts warn that this great and fertile area may become almost as barren as the deserts of Arizona and New Mexico or perhaps the famous Sahara desert, unless the farmers abandon ploughing up all the land each year and let some of it go back to grass, as nature intended a serious upset for the farmers in this vast area of American farm land. The dust storm was a new phenomenon for the East, the Government Forest Service reports, but is becoming an alarmingly frequent occurrence in the Middle-West. For several years in the Great Plains region reports of wheat crops blown out of the ground have been coming in despite the fact that wind velocities, as recorded by the Weather Bureau, have not increased. "This is the way deserts start," declares E. A.

Sherman, associate forester of the Forest Service. "Excessive grazing, which destroys the protective vegetation cover and permits the ground to be trampled into dust, and the plowing up of naturally well sodded grazing lands for grain crops make it easy for the wind to whip away the dry soil and develop into a destructive dust storm. Wind erosion on the plains is like water erosion in States farther East in its power to destroy rich land in a few years." The thing that started the recent storm was drought. For many weeks rain in the Western part of the continent has been deficient. Usually in the Spring of the year the soils of Nebraska and neighboring States either are damp from the Spring rains and Winter snows or are beginning to be covered with young shoots of vegetation.

In either case, the soils are protected reasonably well against the wind. But little loose dust, composed of the soil particles, is raised by any winds except the strongest tornadoes, which usually are local. This year the drought and the rela- other group of gods for admonition or instruction of the populace. In medieval times some of these rains were believed to be tinted by the blood of angels. Finally, only about a century ago, a brilliant German microscopist, Professor Christian Gottfried Ehren-berg, tested samples of blood-rain from Italy and other spots in Southern Europe.

In these samples he found no sign of real blood or any similar material, but only some mysterious reddish dust, resembling ordinary oxide of iron. Side by side with this dust he found, however, articles which he immediately recognized; some tiny skeletons of the one-celled plants called diatoms, belonging to the same plant group as other diatoms known to him as living in German streams and ponds and depositing myriads of their skeletons on the water bottom. Still more surprising was the fact that these diatom skeletons found in the red dust from the blood-rain belonged to kinds of these plants known to be living in oases in the Sahara Desert but not anywhere in Europe. Following up this clue, Professor Ehrenberg soon succeeded in tracing the mystery. He found that sands of Sahara region and in dispelling all of the mystery.

He found that sands of the Sahara contain a considerable proportion of a fine red dust, produced by slow disintegration of certain minerals containing iron. On windy days in the Sahara much of this fine red dust is lifted into the air, together with the coarser sand which makes the sandstorms so dreaded by desert travelers. The coarser sand soon drops when the wind dies down but the finer red dust may float in the air for days. If air currents are moving in the right direction, this dust may drift across the Mediterranean Sea to Europe, fall with the next rain and cause one of the blood-rains honored by centuries of superstitious terror. Dust storms have been proved by violent dust storm, traces of which were observed by vessels far out in the Pacific Ocean.

A few weeks later local dust storms were so severe in the provinces of western Canada that trains were stopped by dust drifts and railway traffic was paralyzed, just as might happen in the Winter from a snow blizzard. The recent dust storm has been called, in fact, a "black blizzard," from its general likeness to these Winter storms. On November 13, 1933, dust particles which fell with a shower of rain in the neighborhood of Philadelphia apparently came from as far away as Kansas, although the quantity of dust carried East on that occasion seems to have been much less than in the recent storm. During the Summer of 1933 exceptional haze was observed over much of the Gulf of Mexico and the Caribbean Sea and was traced to a succession of dust storms over the Southeastern part of the United States. In China dust storms are common, often coming from the dry plains of Mongolia or from the Gobi Desert.

Sometimes vast yellow clouds of this dust are met by steamers hundreds of miles out in the China Sea, In ancient European times, there were many accounts of "blood-rains," Great Britain Bights Beserml. tively cool Spring combined to create vast areas of dry soil covered with loose dust and to slow up the growth of young plants which might have provided another protection against wind. Beginning about the seventh of May a series of strong winds began to blow Eastward across this parched and dusty Western country. Not only was a great deal of dust lifted and blown around locally, as happens every year in the local dust storms of dry countries, but millions of tons of it wore lifted miles high in the air and swept eastward in a gigantic dust cloud covering thousands of f-quare miles. Chicago and its neighborhood got the first taste of the dust cloud.

Toledo, Cleveland, Buffalo, New York and all the East were blanketed in their turn. Although this year's storm may prove to be the greatest dust storm of historical times in the amount of material moved and perhaps in the area affected, many similar storms have been experienced previously. On January 11, 1875, parts of the Middle-West experienced a storm which dropped even more dust on exposed surfaces, although it covered a smaller area than this year's one. In March, 1901, another storm, originating chiefly in Iowa, carried soil particles as far as Vermont. In April, 1931, parts of Oregon and Washington experienced a tS 1931.

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