Tag Archives: cloud-seeding


Irving Langmuir, Bernard Vonnegut, and the Defense Department’s Idea of Weaponizing the Clouds

From the 1930s to the 50s, General Electric company in Schenectady, New York directed the work of its scientists by employing a resident genius to oversee all the laboratories: the first industrial scientist to be awarded a Nobel Prize, Irving Langmuir.


Irving Langmuir, who directed Bernard Vonnegut’s experiments at General Electric

Handsome, outgoing, strenuously athletic, Languir was a Brooklyn-born, European-trained polymath as widely known to Americans in the 1930s and 40s as Stephen Hawking is today. His searching curiosity about scientific questions modeled the kind of thinking he wanted his staff to emulate. He would often preface something he had observed with, “I’m not sure of what use this might be, but.…” And then if a researcher expressed interest in the idea, Langmuir usually would make the resources available.

One day in the spring of 1946, Langmuir was taking a hike on Mount Washington in New Hampshire with Vincent J. Schaefer, his right-hand man at General Electric. Schaefer, a high school dropout, was a self-taught scientist in the Edison mold who rose from machinist at General Electric to Langmuir and Blodgett’s associate. The two men loved skiing and the outdoors, and as they walked they speculated about the weather conditions necessary for precipitation. Rainmaking was the stuff of legend, but for understanding the process of heavy icing— the bane of airports— the role of particles in cloud physics was unclear. Schaefer offered to run some experiments.

What he needed was a way to produce miniature clouds he could observe and alter. He took a horizontal General Electric deep freezer unit, lined it with black velvet and added lights to illuminate a cross-section. When it was finished and turned on, he could make a cloud by breathing into the chamber, the same as seeing your breath in the cold air. He could also make a little cloud of water droplets like those in the higher reaches of a cloud. To try to stimulate his clouds to produce ice crystals, he sprinkled them with talcum, soil, dust— hundreds of agents, but nothing worked.

Returning to his lab on a hot, humid July day, he discovered that someone had turned the unit off. Impatiently, he went down the hall and found a chunk of dry ice, which he dropped into the freezer to help it cool down. To his astonishment, when he breathed into the chamber, a bluish haze sparkled with millions of tiny ice crystals, glinting in the rays of the lights. He had generated the ice cloud from supercooled water droplets. “It was a serendipitous event, and I was smart enough to figure out just what happened…. I knew I had something pretty important.” He replicated the experiment until he established that tiny grains of dry ice would seed the cloud to produce the same effect.

Vincent Schaefer and a pop gun device they invented for seeding their cloud chamber.

Vincent Schaefer and a pop gun device they invented for seeding their cloud chamber.

Langmuir was excited but knew that studying the growth rate of ice nuclei produced by dry ice, calculating the velocity, fall time, and dissipation rate of the ice particles— making real snow in the atmosphere, in other words— would require a lot of work in order to duplicate results obtained in a GE freezer.

He assigned a new man at the company to work with Schaefer— Bernard Vonnegut.

Bernard began a systematic search for creating ice nuclei. He settled in at his desk with basic chemistry texts and studied, over the next few months, the crystal structures of more than a thousand substances. “For no particular reason, I wondered how metallic smokes might work. It was easy to make the smoke from metal by simply producing an electric spark between two electrodes. Among other things, I made a spark with silver coins as the electrodes and was very surprised to get a nice display of ice crystals. But this too wore off after a few tries. Then it occurred to me that maybe this was because of a reaction with the iodine, so I put a little iodine in and, ‘Oh, boy!’ it worked fine.”

Silver iodide smoke was the best candidate. Next, he ran experiments in the cold box, and had not the bottle of silver iodide he was using been contaminated with sodium nitrate, an antifreeze, he would have been credited with developing GE’s first effective means of atmospheric cloud seeding. But Schaefer scooped him by a day.

On November 13, 1946 Schaefer rented a Fairchild light airplane and the services of a professional pilot and took off from the Schenectady County Airport. Langmuir was watching with binoculars from GE. Over Mount Greylock in the Berkshires, thirty miles away, Schaefer dropped three pounds of dry ice pellets into a target cold cloud. As he wrote in his notebook, “It seemed as though [the cloud] almost exploded, the effect was so widespread and rapid.” Snow fell from a cloud layer along a three-mile path in Western Massachusetts. “When we arrived at the airport, Dr. Langmuir rushed out, enthusiastically exclaiming over the remarkable view they had of it in the control tower of the General Electric Lab.”

The next day, a headline in the New York Times heralded the “Opening Vista of Moisture Control by Man.” The accompanying article said “A single pellet of dry ice, about the size of a pea … might produce enough ice nuclei to develop several tons of snow,” or perhaps to disperse sleeting clouds over airports by changing the microclimate A Boston Globe headline read, “Snowstorm Manufactured”.


Irving Langmuir (left) and Bernard Vonnegut (center) observing the effects of small scale cloud-seeding.

It was also the day after Schaefer’s flight that Bernard perfected a second method of cloud seeding. Using a generator that looked like an acetylene torch with a tailpipe, he created silver iodide smoke that produced rapid ice crystal formation in the cold box. Since this appeared to be as effective as Schaefer’s dry ice pellets, GE decided to pursue both techniques. Langmuir, in his first paper on the subject, wrote that “a small amount of ‘nucleating’ agent such as dry ice, silver iodide, or even water could cause a ‘chain reaction’ in cumulus clouds that potentially could release as much energy as an atomic bomb, but without radioactive fallout.”

Weather could be weaponized was the implication. Not surprisingly, the Department of Defense took note. Washington wanted to make certain the United States could beat the Soviet Union in a “weather race,” which, it was rumored, was already underway. In August 1953 Congress created the Presidential Advisory Committee on Weather Control. After deliberating, the committee reported that several scenarios were possible for using weapon as a weapon of warfare. Airplanes could drop exploding balloons, loaded with seeding crystals and the ensuring downpour would turn enemy roads into soup. The Army Ordnance Corps believed it was possible to outfit fifty-caliber tracer bullets of fighter planes with silver iodide and pilots would, in effect, strafe the clouds. And then there was idea of striking at the enemy populace by making it rain before clouds reached their farmland— similar to starving out the defenders of a castle.

Were clouds ever weaponized? Several sources say that the method was used in Vietnam. But then both Langmuir and Bernard Vonnegut were long gone from General Electric.

Much more about Bernard, and Kurt Vonnegut, who served as a public relations representative at General Electric during those years, can be found in Ginger Strand’s, The Brothers Vonnegut: Science Fiction in the House of Magic.