APPENDIX 
REPORT ON THE ASTROPHYSICAL OBSERVATORY 
Str: The Astrophysical Observatory was conducted under the 
following passage of the independent offices appropriation act ap- 
proved March 3, 1925: 
Astrophysical Observatory: For maintenance of the Astrophysical Observa- 
tory, under the direction of the Smithsonian Institution, including assistants, 
purchase of necessary books and periodicals, apparatus, making necessary 
observations in high altitudes, repairs and alterations of buildings and mis- 
cellaneous expenses, $31,180, of which amount not to exceed $26,840 may be 
expended for personal services in the District of Columbia. 
The observatory occupies a number of frame structures within 
an inclosure of about 16,000 square feet south of the Smithsonian 
udministration building at Washington, and a cement observing sta- 
tion and frame cottage for observers on a plot of 10,000 square feet 
leased from the Carnegie Solar Observatory on Mount Wilson, Calif. 
Since October, 1925, the observatory building on Mount Harqua 
Hala, which we have occupied since 1920, has been closed because the 
work has been removed to Table Mountain, Calif. By the generosity 
of Mr. John A. Roebling, a tunnel for instruments, a dwelling for 
the field director, a shop, and a garage have been constructed at 
the new site. A dwelling for the assistant is also contemplated 
within Mr. Roebling’s grant. 
During the year the Astrophysical Observatory has assumed part 
of the cost of the maintenance of the observing station at Monte- 
zuma, Chile, which was erected in 1920, with means furnished by 
Mr. Roebling. The constructions there comprise a tunnel for instru- 
ments, a dwelling, shop, and garage, and a telephone line 12 miles 
to Calama. 
The present value of the buildings and equipment for the Astro- 
physical Observatory owned by the Government is estimated at 
$50,000. This estimate contemplates the cost required to replace 
the outfit for the purposes of the investigation. 
WORK OF THE YEAR 
A new station—The National Geographic Society, having become 
interested in our efforts to obtain an accurate series of measurements 
of the variation of solar radiation, made a grant in March, 1925, of 
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