150 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1920. 



walls of the little stone hut for my work, and they finished it, including the 

 roof, that day. Several 6 by G tents had been loaned by Professor Campbell, 

 and in these we cooked, ate, and slept. Ham, bacon, Mulligan stew, and flap- 

 jacks were the staple foods. 



I had set up my apparatus mainly by Thursday night, August 26. Friday it 

 snowed a little, but the house was finished Friday afternoon, August 27. 



Mr. Campbell, with Messrs. Albrecht, McAdie, Doctor Miller, Hoover, and 

 Skinner, came about noon on Saturday, August 28. They arrived in a thunder- 

 storm of sleet. Lightning struck near by just as they reached the door. It 

 became partially clear on the following Wednesday, and Campbell secured good 

 observations on Wednesday and Thursday nights. My own preparations were 

 set back by the storm, so that I only got ready Thursday afternoon, September 

 2- Friday morning was beautiful, and I think my observations of that fore- 

 noon were satisfactory. I took two holographs also about 2 and 5 p. m. of 

 Friday afternoon between clouds. On Saturday it snowed 4 inches. Mr. 

 Campbell and party went down. They almost lost one mule among the rocks 

 (had to leave the mule behind after two hours' work, but it went down the 

 trail the following Wednesday), and three others slid off of the ice on the east 

 side *of the range and rolled a hundred feet or so. The Smithsonian has been 

 so fortunate as not to have had any of the animals in its employ injured during 

 the whole operations. After waiting several days without much improvement 

 in the weather Mr. Marsh and I left on Wednesday, September 8. I hope it 

 will be possible for me to complete my work up there next July or early August, 

 when the weather will probably be better. 



In August, 1910, the writer again ascended Mount Whitney with 

 Mr. Marsh, and in the course of 10 beautiful days there again set up 

 the spectrobolometer and obtained excellent "solar constant" ob- 

 servations. 



Simultaneous measurements made in 1909 and 1910 at Mount 

 Wilson and Mount Whitney agreed within about 1 per cent and 

 within the error of the determinations. Similar agreement had been 

 obtained before that between simultaneous measurements at Wash- 

 ington and Mount Wilson, so that there appears to be no effect on the 

 "solar constant" results depending upon differences of altitude, at 

 any rate up to 14,500 feet. 



MOUNT WILSON. 



With the establishment of the Carnegie Institution in 1902, many 

 plans for work in all branches of science were submitted, among them 

 one by Doctor Langley, then Secretary of the Smithsonian Institu- 

 tion, on the measurement of solar radiation. He entertained the hope, 

 which has since come very close to fruition, that a knowledge of the 

 sun's radiation, the losses which it experiences in passing through our 

 atmosphere, its possible variability from time to time, would be such 

 a boon to meteorological science as to be a basis for forecasts of long 

 range such as might even parallel those of Joseph, who forecast the 

 seven lean years and the seven years of plenty. 



