REPOET OF THE SECEETAEY. 189 



Such a system of normals develops many interesting and important 

 cosmical problems, especially those regarding the seasonal variation 

 of the climate and the forecasting of the weather conditions for 

 longer intervals than at present practicable. 



In 1907 the daily temperature normals, computed for a period of 

 33 years, 1873 to 1905, inclusive, were published. 



In 1894, in accordance with the recommendation at the Interna- 

 tional Conference at Munich of 1891, resolutions were passed by the 

 committee on cloud observations, inviting all countries to coop- 

 erate in cloud observation work beginning May 1, 1896. The 

 Weather Bureau conducted these observations at 15 stations throuo-h- 

 out the United States, and from these observations deductions were 

 made as to the height of all classes of clouds. The " Report on the 

 International Cloud Observations," May 1, 1896, to July 1, 1897, was 

 published as Volume II of the Report of the Chief of the Weather 

 Bureau, 1898-99. 



MOUNT AVEATHER (VA.) RESEARCH OBSERVATORY. 



The plan to found an observatory at Mount Weather, Va,, for 

 research work took definite form in 1903, in which year a site was 

 obtained on the summit of the Blue Ridge, 6 miles south of Blue- 

 mont, Va. The main building was erected in 1904, but in October, 

 1907, it was destroyed by fire. In 1909 a fireproof structure was 

 erected on the foundation of the old building, a central heating and 

 poAver plant was also constructed, and several buildings which had 

 been begim at an earlier date were completed. 



While the buildings were being constructed scientific work was 

 carried on under difficulties. Surface meteorological observations 

 were begun in November, 1904, and the results have been telegi-aphed 

 to Washington daily since that time. The years 1905, 1906, and part 

 of 1907 were spent in installing and testing instrumental equipment 

 and in experimental work preparatory to the exploration of the free 

 air, which at that time seemed to be a promising subject of investi- 

 gation. 



EXPLORATION OF THE TIPPER AIB WITH KITES. 



While some experimental kite flights were made as early as the 

 autumn of 1905 the regular program of daily flights on week days 

 did not begin until the summer of 1907, and it was not until July, 

 1909, that flights on Sundays were included in the regular program. 

 The effort to get a daily sounding in all sorts of weather conditions 

 has been a sustained and fairly successful one. In the four years, 

 1909-1912, there were but 39 days on which it was not possible to 

 make a kite flight or captive-balloon ascension. Wien weather con- 

 ditions were not favorable many of the flights naturally extended 



