Such seemingly unconnected phases of science as the forecasting of weather, the fertility of plants, and a machine which will eventually displace coal and gasoline engines are actually linked together through the medium of the sun's rays, according to Charles G. Abbot, secretary of the Smithsonian Institute in Washington.

A guest this week at Harvard and at his alma mater, M.I.T., Dr. Abbot discussed the latest developments in the knowledge of the effects of the sun in the course of a visit to the University Observatory yesterday.

"The energy of the sun in New Mexico or Florida could furnish all the power needed for the industries of the United States," he stated. "We are working at present on a machine to utilize this solar energy; we have a very effective one but it needs to be put into wholesale use before it will be practical."

Low Upkeep Cost

Citing the advantages of using such a machine powered by the sun's rays, Dr. Abbot pointed out the low cost of upkeep. Although at present its costs are about the same as those of a coal engine, one-half cent per horsepower hour, if the machines could be made in large quantities there would be no fuel charges at all.

"The chief disadvantage would be that the sun is intermittent and the machine would not work at night or on cloudy days," he said. "But power can be converted into electric power, compressed air, or superheated water and saved up for the periods when the sun is not out."

Shifting to the topic of the weather, Abbot voiced his "pet" theory that all changes in weather are caused by fluctuations in the intensity of the sun's rays.

"These vary from one to three per cent of the total intensity," he said, "but even a very slight variation causes a change in atmospheric conditions which controls all the phenomena of the weather.

"By taking an observation in Chile and by using facts that we already know of weather conditions in China, for instance, or in Boston, we can predict the weather in those places for two weeks in advance."

Experiments are also being made with ultra-violet rays, Dr. Abbot mentioned.