ELECTRICALLY CHARGED SAND DISPERSES CLOUDS

"There is no doubt but that the experiment works", was the reply which Professor E. L. Chaffee G. '11, Associate Professor of Physics at the University, made to a CRIMSON reporter last night, when interviewed concerning the work which is being carried on by the United States Government to determine whether or not electrified sand scattered by airplanes will cause clouds and fog banks to disappear.

Government Financed Work

The invention of this device has been credited to "Dr. L. Francis Warren, of Harvard University". Mr. Warren, he is not a Doctor, has no official relations with the University. Mr. Warren though of the original idea and came to ask Professor Chaffee's advice. The Government became interested in the proposition and undertook to finance it. Professor Chaffee then began research work to determine if sand particles could be electrically charged, and if so what was the most practicable method of obtaining this charge. All of these experiments were carried on by Professor Chaffee at the Cruft Laboratory at the University with the help of Mr. R. O. Chaffee '17. the two brothers invented a revolving nozzle, which rotates by centrifugal force, and causes the sand to fly out. This nozzle contains an internal and an external electrode, and is driven by an alternating generator installed on the plane. By turning a small lever one way or the other the direction of the current may be changed, and the sand particles thus charged either positively or negatively. Early last spring permission was obtained from the University authorities for airplanes to land on Soldiers Field for the first time in the history of the University. These planes were then equipped with Professor Chaffee's patent nozzle, and departed to test the value of the invention.

Test Peace and War Value

At present the Government is taking great interest in the experiments, and daily flights will be made at Boiling Field during the next six weeks to determine both the peace and war value of the invention in connection with aviation.

The work is based on the assumption that visible forms of moisture in the air, such as mists, clouds, and fogs, are a form of colloidal suspension in gases and should be governed by the same general laws that prevail in colloidal action in liquids and solids. The sand tanks on the airplanes are flied with 120 mesh silica sand. When a cloud in found to have a negative charge positively charged particles are scattered at the extreme top; when the cloud has a positive charge negatively charged sand particles are scattered at the extreme top; and if the cloud has no charge, it is first charged one way, and then dispersed by attacking it with the opposite charge. The clouds immediately condense and disappear. if is possible, according to Professor Chaffee, for the Government to keep their large cities, landing fields, and harbors free from fogs and dense clouds, by using larger planes, which could scatter electrified sand at the rate of 100 pounds per minute, the maximum amount of sand which the planes now being used in the experiments can scatter.

In closing Professor Chaffee said that, although it might be possible to cause rain to fall by the use of the electrified sand, no real proof of this had as yet been obtained. He said it might be possible to produce rain in regions where large moisture clouds were present at fairly low altitudes, but that it would be absolutely impossible to produce rain under any other condition