A major scientific development, which will mean the saving of thousands of dollars worth of electric power annually through increased efficiency of the vacuum tube, or "electric valve," in controlling electricity, was announced last Wednesday by the Cruft Laboratory of Communication Engineering.

The findings, which are considered to be one of the greatest contributions to the development of the use of power vacuum tubes in recent years, are the result of ten years' work in the Harvard laboratories by Emory L. Chaffee, Gordon McKay Professor of Physics and Communication Engineering.

Chaffee has developed the first satisfactory methods of testing the complex operation of vacuum tubes and thus increasing their efficiency through scientific and mathematical analysis.

In replacing the relatively crude, haphazard, and extremely expensive method of improving vacuum tube performance by trial and error, hitherto universally applied, Chaffee is believed to have opened the way to much wider development and use of the electric "valves."

His work is regarded by authorities as a signal triumph of laboratory and mathematical skill over one of the most complex problems in electrical engineering posed before this generation.

While the vacuum tube is one of the most vital tools of modern industry and science, with hundreds of millions of units now in operation, the tube has been developed slowly in efficiency because of the forbidding jungle of interlocking mathematical functions involved in its operation.

The intricacy of the formulas involved is indicated by the fact that in any vacuum tube the electric potentials applied present four variable factors, all reacting to the slighest deviation of any one.

For the first time through the techniques developed by Chaffee, engineers are able to resolve these variables through mathematical calculations backed by routine laboratory tests,--thus arriving rationally at more efficient combinations of the variables.

In their first immediate application to industry, Chaffee's findings are expected to affect markedly the manufacture and use of the giant power tubes through which radio stations daily control and transmit hundreds of thousands of kilowatts of electrical energy.

The Harvard work shows that in many cases the tubes now in use in radio broadcasting may be so altered and activated that their power output may be doubled, and their efficiency greatly increased.

Besides the complexity of performance, a major hindrance to experimentation with the huge power tubes, which sometimes are as much as six feet high, has been their cost, about $5,000 a unit.

Chaffee has developed the first technique by which tests of the behavior of large power tubes can be made with small models.

This extension of so-called dimensional analysis, used for years in the design of turbines, ships, and airplanes, into the highly complicated region of the interaction of electrical potentials, is regarded as one of the most brilliant of Chaffee's accomplishments.

Use of the small scale model in only one of four methods of investigating power tube operation achieved by Professor Chaffee.

Using one of his methods, it is possible to calculate the performance of a tube from graph curves based on the characteristics of the unit.