Appendix 5. 

 EEPORT ON THE ASTROPHYSICAL OBSERVATORY. 



Sir : I have the honor to present the following* report on the opera- 

 tions of the Smithsonian Astrophysical Observatory for the year 

 ending June 30, 1914 : 



EQUIPMENT. 



The equipment of the Observatory is as follows : 



{a) At Washington there is an inclosure of about 16,000 square 

 feet, containing five small frame buildings used for observing and 

 computing purposes, three movable frame shelters covering several 

 out-of-door pieces of apparatus, and also one small brick building 

 containing a storage battery and electrical distribution apparatus. 



(&) At Mount Wilson, Cal., upon a leased plot of ground 100 

 feet square, in horizontal projection, are located a one-story cement 

 observing structure, designed especially for solar- constant measure- 

 ments, and also a little frame cottage, 21 feet by 25 feet, for observer's 

 quarters. 



Upon the observing shelter at Mount Wilson there is a tower 40 

 feet high above the 12-foot piers which had been prepared in the 

 original construction of the building. This tower has been equipped 

 with an improvised tower telescope for use Avhen observing (with 

 the spectrobolometer) the distribution of radiation over- the sun's 

 disk. 



Other pieces of apparatus for research have been purchased or 

 constructed at the Observatory shop. The value of these additions 

 to the instrumental equipment, not counting the tower above men- 

 tioned and its equipment, is estimated at $1,500. 



WORK OF THE OBSERVATORY. 



AT WASHINGTON. 



Observations. — Mr. Fowle has continued the difficult research on 

 the transmission through moist air of radiations of great wave 

 length, such, for instance, as those which bodies at the temperature 

 of the earth emit most freely. He uses a very powerful lamp made 

 up of a large number of Nernst electric glowers, and examines by 

 the aid of the spectrobolometer the energy spectrum of the rays 



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