Weather or Not

(See Cover)

In their various fashions, the people of New Mexico had long prayed for rain. They were used to seeing the Rio Grande shrunk to a brookwide trickle, too thick to drink, too thin to plough. They were used to seeing their reservoirs low, their rolling ranges burned brown. Often they were forced to ship their cattle away to greener pastures. Many a sun-scorched New Mexican had said resignedly: "The Lord made the state dry. I guess He wants it that way."

Nevertheless, on the slopes above Socorro, a group of scientists thought it no impiety to see what could be done about changing New Mexico's weather. With a radar they searched the dark hearts of thunderclouds. Their potentiometers felt the pulse of lightning. They had a B-17 heavy-laden with strange apparatus, bristling with instruments like a flying porcupine. They had movie cameras, cylinders of butane and walkie-talkie radios.

And they were not the only ones. Last week, after July's plentiful rainfall, most of the state's cattle ranges were greening out. Farmers and ranchers in northeastern New Mexico gave the credit to a private rainmaking company which they had hired. All over the Southwest, and here & there throughout the rest of the U.S., a rainmaking boom was on. Many of the rainmakers were amateurs. But some were serious and hopeful scientists or hard-headed businessmen.

Reproachful Looks. In thirsty Arizona, the most successful is Charles Barnes of Phoenix, a first-class flying man who, with 17 airplanes equipped or being equipped for rainmaking, had seven projects going full blast from Texas to California. Another big rainmaker is Irving Krick of Pasadena, Calif., who has projects in New Mexico, Colorado, California, Idaho and Washington. Best publicized of the lot is Harvard's Dr. Wallace Howell, hired last March by New York City (at $100 a day for a maximum of 15 days a month) when the great reservoirs in the Catskills and Westchester County were far below normal and New Yorkers were being urged to save every dribble of water.

All of them worked on the principle of spraying dry ice or silver iodide into fat, moisture-laden clouds, forcing them to disgorge their watery vapors which fall as rain. The man behind the principle was an energetic, 69-year-old scientist named Dr. Irving Langmuir.

Until Irving Langmuir began poking into the subject, meteorology was a passive science. Meteorologists observed and tried to forecast the weather, but when asked why they didn't do something about it, they simply looked reproachful. Modern meteorological engineering--the technique of doing something about it--was born four years ago in Langmuir's General Electric laboratory at Schenectady.

Very Small & Very Large. No meteorologist to begin with, Brooklyn-born Irving Langmuir was educated at Columbia University and Gottingen in Germany, settled down to teach chemistry at Hoboken's Stevens Institute of Technology. In 1909 he joined General Electric's Research Laboratory, where he found the freedom he wanted to do research.

His G.E. bosses told young Langmuir not to bother about practical applications of his experiments, to look around the laboratory and work on anything that interested him. G.E.'s investment in non-routine research soon paid off. Langmuir became associate director of G.E.'s Schenectady laboratory, worked on such eminently practical things as high-vacuum radio tubes, and the gas-filled light bulb, which, says G.E., saves the U.S. public nearly $1 billion a year in electric bills by lengthening the filament's life.

Langmuir's theoretical work was even more important. Most of it concerned the extraordinary potency of very small things: electrons, molecules, thin films and infinitesimal particles. Over the years Langmuir became an authority on the David & Goliath contests between the very small and the very large, in 1932 won a Nobel Prize for his discoveries in that field.

But, like everyone else, Langmuir did nothing about the weather (except complain about it) until World War II, when he began studying the water droplets in high, cold clouds which freeze into deadly ice on airplane wings. He was drawn away to other urgent war jobs before he found out all he wanted to know about those droplets. But he did not forget them. He suspected that they might answer an important question: Why does it rain?

Ice & Water. The schoolbook explanation of rain is that "clouds condense into raindrops and fall to the ground." It is not quite as simple as that. Unless something special happens to it, a cloud remains a cloud; the droplets in it stay about as they are, too small to fall.

After the war, Langmuir went back to work on the mystery of rain clouds. He knew that the droplets in clouds do not freeze at 0DEG C. (32DEG F.). They are supercooled, i.e., are much colder than zero centigrade, the normal freezing point. When an ice crystal comes in contact with supercooled droplets, it can steal water from them, so water vapor moves from the droplets to the ice. The ice crystals grow; the droplets shrink.

Langmuir reasoned, as others had before him, that this process might be a cause of rain and might show a way to make artificial rain. If small ice crystals could be induced to form in a supercooled cloud, they should grow into big snowflakes at the expense of the cloud's droplets, then fall to the ground as snow, or melt into rain.

Langmuir and his brilliant young protege, Vincent Schaefer, a onetime machinist, settled down in G.E.'s Schenectady lab and began experimenting with a cloud in a test tube. Their "test tube" was an ordinary G.E. home freezer lit by a slanting beam of light and lined with black velvet for better visibility. All they had to do to make a "cloud" was to breathe into the chamber. Making the crystals in the cloud was something else again.

Langmuir and Schaefer tried all kinds of things, with no success. Then, one hot day in July 1946, Schaefer was alone in the laboratory. The cold chamber was not quite cold enough to suit him, so he put in a hunk of dry ice (temp. --79DEG C., --110DEG F.). At once he saw bright motes swirling through the light beam. As he watched, they grew into glittering snowflakes and settled to the bottom of the chamber.

The Cold Does It. Langmuir, the man of theory, soon worked out the "mechanism." It was the low temperature of the dry ice, not its carbon dioxide, that did the trick. Any very cold object, e.g., a needle cooled with liquid air, served as well.

How cold is cold enough? Langmuir and Schaefer found by careful experiment that the motes form at -39DEG C. (38DEG F.). This explained some types of rain. Certain clouds rise high enough to be cooled to that temperature. Ice motes form, find their way into warmer parts of the cloud, where they grow into snowflakes and fall as snow or rain. "Why not help things along with some dry ice?" asked Langmuir & Schaefer.

One day in November 1946, Schaefer took off from Schenectady in a small airplane and directed the pilot to a fleecy cloud four miles long that was floating over nearby Massachusetts. When he reached it, he scattered into it six pounds of dry ice. Almost at once the cloud, which had been drifting along peacefully, began to writhe as if in torment. White pustules rose from its surface. In 5 minutes the whole cloud melted away, leaving a thin wraith of snow. None of the snow reached the ground (it evaporated on the way down), but the dry ice treatment had successfully broken up a cloud.

Bath in the Clouds. This dramatic feat stirred up a flurry of premature rainmaking. Barnstorming pilots took off with dry ice to knock down fleecy clouds. They did not knock down much rain. For one thing, they often picked on the wrong clouds, e.g., the stratiform (layerlike) clouds, which unless very thick do not contain enough moisture to matter. And they were inclined to overdo, choking the clouds with too much dry ice. A piece of dry ice falling through a supercooled cloud creates enormous numbers of ice nuclei. Too many falling pieces of dry ice create too many nuclei; they compete fiercely for the water in the cloud, but there isn't enough to go around. Result: a dense cloud of ice crystals too small to fall.

Dry ice, Langmuir soon decided, has other limitations. It affects a cloud only while falling through it, and the ice motes it creates must take effect immediately or they will evaporate. Dr. Bernard Vonnegut, another of Langmuir's bright proteges, was assigned the job of finding some sort of permanent, nonvolatile particles that would hang in the air long enough for ice to form on them.

Water, reasoned Vonnegut, forms hexagonal ice crystals with well-known characteristics. If another hexagonal crystal could be found with nearly the same characteristics, the water molecules in the air might be fooled into building up on it as if it were a genuine ice nucleus.

Vonnegut thumbed through fat books on crystallography. At last he spotted a promising compound: silver iodide. Its molecules do not resemble water molecules, but they build into crystals almost exactly like those of ice.

The first trial was a failure; Vonnegut's commercial silver iodide was too impure. He tried again with a few specks of pure silver iodide, which he evaporated from an electrically heated wire. At once the captive cloud in his cold chamber turned into snow. The merest smidge of the magic iodide seemed to be enough.

Magic Tool. Here apparently was a tool of almost miraculous potency. Like dry ice, silver iodide could be injected into clouds from a plane; it could also be sent up as a smoke of fine particles from a generator on the ground. When the G.E. men considered its possibilities, they were appalled. If all the earth's supercooled clouds were turned into rain at once, what would happen to the world's climate? Langmuir estimated that only 200 pounds of silver iodide would be enough to seed the earth's entire atmosphere. The G.E. men dandled their newfound silver iodide, an innocent-looking yellow powder, and wished it were not quite so easy to spray it into the air.

With such a handy device available, they also foresaw a prospect of endless legal problems. Langmuir and his co-workers had already had one forewarning. In the winter of 1946, Langmuir's men gave the dry ice treatment to a mass of clouds near Schenectady. Snow started falling. It fell & fell. The storm had all the usual effects of a blizzard: snarled traffic, accidents, a drop in business for department stores. It would be hard to prove that the dry ice was responsible (if it was), but the incident gave G.E. a serious scare. The big, rich company would be a tempting target for damage-suit lawyers.

General Electric was much relieved when the Army got into the game with its Project Cirrus in 1947, borrowed Langmuir and Schaefer as advisers, later moved many of their operations to New Mexico, where the air is pure, where clouds often come singly and where the people quite sincerely welcome rain. Says Dr. Chauncey G. Suits, director of research: "G.E. has disassociated itself legally from rainmaking in the fanciest ways it can think of."*

Heated Debate. Langmuir's chief interest in New Mexico has been cumulus louds, the tall, billowing formations which sometimes turn into thunderstorms. In much of the U.S. they cause most of the summer rainfall. During New Mexico's summer rainy season (which is not very rainy), there are plenty of towering cumulus clouds, but about nine out of ten of them march magnificently across the sky and vanish without shedding a drop. Near Albuquerque in July 1949, Langmuir performed an experiment that is still debated heatedly and at length in meteorological circles. He started his silver iodide generator early on a morning when the Weather Bureau had predicted no substantial rain. Then he watched developments with a radar.

At 8:30 a.m. a cloud started growing 25 miles away downwind. When the cloud reached 26,000 feet, it suddenly spurted, bulging upward at 15 m.p.h. Soon a radar echo showed that the cloud was full of rain or snow. Heavy rain fell near the Manzano Mountains. A short while later, a second cloud showed a similar convulsion and also produced heavy rain.

Langmuir insisted that both these thunderstorms formed in the "trajectory" of his silver iodide particles and at about the time when the particles must have been entering their bases. He therefore took credit for the rain they dropped as well as for other rain from later storms.

Softening Opposition. Many authorities did not agree with him. Langmuir's theories have been attacked by the U.S. Weather Bureau, by civilian and military meteorologists. In 1948 the Weather Bureau tried its own cloud-seeding experiments, dumping dry ice and silver iodide into clouds in Ohio. No significant rain fell from them. Langmuir's explanation is that the clouds were the wrong kind in the first place, and that they were greatly overseeded.

Some conservative meteorologists are still arguing with Langmuir & Co. Their position is that all weather effects are produced by the "synoptic situation," the complicated interaction of air masses of varying temperatures, pressure and wind velocity. All "artificial" rain, they insist, would have fallen anyhow, without man's help. The July 1949 rainfall in New Mexico, for instance, they attribute to a front moving in from the Gulf of Mexico.

The Weather Bureau has shown recent signs of softening its opposition. Its chief, Dr. Francis W. Reichelderfer, gives Langmuir and Schaefer full credit for showing how a cloud can be precipitated. Reichelderfer agrees that certain special clouds, such as the cold clouds which form over mountains, can be seeded profitably. But he thinks Langmuir's claims are too sweeping. "My impression," he says, "is that Langmuir and his associates were successful in speeding up the rain formation process in a few cases, but I feel quite sure that in many cases the rain was due to natural causes."

Farmers' Lament. Some of the rainmakers themselves hesitate to claim positive results from their efforts. Operating in the same touchy area where Irving Langmuir started, New York's Dr. Howell was warned that if he talked too much about dumping rain on the watersheds New York City might be sued by outraged farmers and resort owners in the Catskills. Until a fortnight ago he never mentioned his results. Then he cautiously admitted that his efforts had produced "a certain amount" of rain. In the same breath he suggested that on some occasions they might also have lessened the normal rainfall by overseeding.

In any case, New York City was satisfied enough to extend Howell's contract for another six months and the reservoirs are all now nearly full, a rare condition at this season. Upstate New Yorkers are even more belligerently certain of his success.

Just after Howell got busy with his planes and generators, New York began having a miserable spring and early summer of warm rains, cold drizzles and sticky fogs. In the Catskills it rained and rained. The important sweet corn crop was badly damaged; weeds grew high in fields too. gooey to cultivate. Farmers threatened to shoot Howell; so did resort owners. "Look," said Julius Slutsky, a proprietor of the upstate Nevele Hotel (which tried to sue New York City), "our guests come from New York City. They don't know much about the country. They say, 'They got rainmakers up there, so why should we go up to Slutsky's?' "

What Do Ants Do? As a cautious scientist, Irving Langmuir himself would never go so far as Julius Slutsky's guests. But he is convinced nonetheless that man can make rain if he goes about it at the right time and in the right way.

At 69, he is a stocky man of middle height with plentiful white hair and an air of semi-polite skepticism. But he can also blaze with indignation and laugh like a kid--all within a few minutes. In the presence of his gentle-voiced, humorous wife, he smiles like a man who is happy. His interests are more versatile than those of many scientists: he has been known to sit for half an hour beside a rock surrounded by rising water just to see what a dozen ants will do when their refuge is submerged.*

On his present project in New Mexico he now spends most of his time with his eyes fixed on the hot summer skies, watching for new clouds to conquer. He has teamed up with Dr. E. J. Workman, president of the New Mexico School of Mines, who has begun a new series of experiments, studying the electrical habits of thunderstorms.

So far neither Langmuir nor Workman is overanxious to publish their latest results. Both feel that too much silver iodide is being sprayed around the Southwest these days. It might be just as well to leave matters as they are for a while before western clouds are overseeded or the chemicals drift to the east and cause too much rain.

The Desert Maiden. In front of the new white laboratory of Workman's New Mexico School of Mines in Socorro stands a brick-red statue of an ethereal young girl holding a bird at her bosom. The students call her "the desert maiden," but Dr. Workman says she is Santa Rita, "Patron Saint of the Impossible," and just the right patroness for a physics lab.

Santa Rita used to be in Albuquerque, where her bird was thought to be a dove. Now that she has moved to Socorro and the rainmaking studies are going full blast around her, it has been noticed that her bird looks more like a duck. It holds its head back on its shoulders in a way doves seldom do. Dr. Workman considers this apparent metamorphosis a favorable omen.

Langmuir laughs and says: "We'll have to wait and see." With his radars and pocket thermometer, his optimism and his energy, he hopes to make ducks & drakes, some day soon, of New Mexico's perennial drought.

*No state as yet has a law to regulate rainmaking; Colorado is considering one.

*In the end, they drown.

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