Appendix V. 



REPORT OF THE WORK OF THE ASTROPHYSICAL OBSERVATORY FOR 

 THE YEAR ENDING JUNE 30, 1904. 



Sir: The kinds and amounts of Observatory property are approximately as follows: 



Buildings $6, 300 



Apparatus 41 , 400 



Library and records 6, 800 



Total 54, 500 



During the past year the acquisitions of property have been as follows: 



(a) Apparatus. — Astronomical and physical apjiaratus has been purchased at an 

 expenditure of $4,500. The most important pieces comprise a new spectrobolometric 

 outfit, to be used in the study of the great solar image of the 140-foot focus horizon- 

 tal telescope, and also for a proposed expedition to some elevated station for the 

 determination of the solar constant. Of the sum expended for apparatus, $2,430 was 

 chargeable to the appropriations of 1901-2 and 1902-3. Shelters for the great hori- 

 zontal telescojje and ajjparatus for the research on the solar constant have been 

 ordered, at an estimated exjjenditure of $1,230. A ground plan of the Observatory 

 enclosure, including the new shelters, is shown in Plate Y. 



(b) Library and records. — The usual periodicals have been continued, and a few 

 books of reference purchased. Three new cases have been procured for storage of 

 books and periodicals. The total expenditure for these purposes is $340. 



The Observatory buildings have been repainted at a cost of |195. No losses of 

 property worthy of note have occurred during the year. 



THE WORK OF THE OBSERVATORY. 



For convenience the work may be classified as follows: 



1. Publications and miscellaneous matters. 



2. Improvements of apparatus. 



3. Investigations. 



1 . Publications and miscellaneous matters. 



Eclipse report. — The rejiort of the solar eclipse expedition to Wadesboro, N. C, of 

 May, 1900, referred to in my last year's report, has been distributed, and has been 

 favorably noticed both in this country and abroad. 



St. Louis Exposition. — .\ far more elaborate exhibition of the Observatory work 

 than usual has been prepared and installed for the St. Louis Exposition under your 

 instructions. The great coelostat, mentioned in my last year's report, is arranged to 

 throw a beam of sunlight into a darkened portion of the room occupied by the 

 Observatory exhibit, where a solar image about a yard in diameter is thrown up l)y 

 a 6-inch telescope, and the solar spectrum is formed upon the walls of the room by a 

 large concave grating. 



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