APPENDIX 8 
REPORT ON THE ASTROPHYSICAL OBSERVATORY 
Sir: I have the honor to submit the following report on the opera- 
tions of the Astrophysical Observatory for the fiscal year ended June 
30, 1948: 
The Observatory organization comprises the office of the Director 
(which includes three shops for the preparation of equipment: the 
wood, glass, and metal shops) and two research divisions: (1) the 
Division of Astrophysical Research and (2) the Division of Radiation 
and Organisms. 
In September 1947 W. H. Hoover was promoted to be Chief of the 
Division of Astrophysical Research. Mr. Hoover has been a member 
of the Observatory staff since 1923. It is a sad duty to record the 
death on December 17, 1947, of Dr. Earl S. Johnston, Chief of the 
Division of Radiation and Organisms. Dr. Johnston joined the divi- 
sion at its beginning in 1929 and was responsible for a large portion 
of its development in recent years. Before the close of the fiscal year 
the Observatory was fortunate in completing arrangements to have 
Dr. Robert B. Withrow, of Purdue University, succeed Dr. Johnston 
as Chief of the Division, beginning September 1, 1948. During the year 
Dr. R. L. Weintraub, biochemist, and L. B. Clark, expert glass blower 
and technologist, transferred to National Defense agencies. 
(1) DIVISION OF ASTROPHYSICAL RESEARCH 
The year may be characterized as one of exploration and develop- 
ment since considerable effort was expended in search for a suitable 
high-altitude site for a third solar station, and in planning and pre- 
paring new equipment. It is proposed at the new station not only 
to conduct routine solar-constant observations, but also to test new 
electronic equipment and to conduct special researches. One project 
planned is a day-to-day study of changes in the infrared band of ozone 
at 9 microns wave length. For this work a special double spectroscope 
designed by Dr. Abbot, research associate, is being constructed by the 
Gaertner Scientific Corporation. New mirrors, aluminized and coated 
with magnesium fluoride, for both coelostat and spectrobolometer are 
on order. A fused-quartz prism, very free of bubbles, has been com- 
pleted, also a new vacuum bolometer. The bolometer, planned and 
built by L. B. Clark, is so designed that the vacuum around the bolom- 
121 
