REPORT OF THE SECRETARY IQl 



ADDITIONAL SOLAR STATIONS 



Great hope had been aroused by favorable action of the Senate in 

 June 1936, with approval of the President and the Bureau of the 

 Budget, that as many as seven additional stations for observing the 

 solar constant of radiation could be established. But the hoped-for 

 appropriation having failed in the House, the item was rejected by 

 the Bureau of the Budget in the estimates for 1938, and with the 

 present stress on economy in Government expenditure seems un- 

 likely to be revived. It is still believed that valuable advance in 

 weather forecasting would follow the accurate daily determination 

 of solar variation, such as might be attained with additional solar- 

 constant stations. 



LONG-KANGE FORECASTING, LAKE LEVELS, AND TREE RINGS 



Letters have been received nearly every day by the Director from 

 drought-stricken areas, some telling of observations confirmatory 

 of his expectations as to the progi'ess of the drought, but most of 

 them begging for predictions to cover ensuing years. The Director, 

 in his replies, has always pointed out the insecurity of such predic- 

 tions. He has limited himself to referring to indications arising 

 from the history of Great Lakes levels since 1837. These point to a 

 probability that drought conditions in the Northwestern States and 

 neighboring Canada will mend beginning in 1938, but recur in 1975. 

 This view is supported by a record of 400 years' duration in tree 

 rings at Fairlee, Vt., measured by Professor Lyon, of Dartmouth 

 College. Periodicities of 23, 46, and 92 years are plainly apparent 

 therein, which have close relations to the levels of the Great Lakes. 



SOLAS ENGINE 



The Director caused to be prepared and tested in September 1936 

 a solar radiation steam boiler of his design. The machine is repre- 

 sented in the accompanying illustration. It exposed 36 square feet 

 (pi. 7) of mirror surface and was intended to produce about % horse- 

 power at the engine. Cinematograph records were made of it, and by 

 ojjerating an electric generator a short program was broadcast by 

 solar power. However, the device had many defects, and was not in 

 that form practical for utilizing solar radiation for power. A small 

 solar flash boiler has since been prepared which offers much greater 

 promise. 



FIELD WORK 



Solar radiation observing stations have been maintained by public 

 funds, supplemented by private resources of the Smithsonian Insti- 



