114. ANNUAL REPORT SMITHSONIAN INSTITUTION, 1946 
of the spectrum most active, in the degradation. The development of 
suitable instruments and methods for this radiation study at Camp 
Lee, the installation of the equipment, and the organization of the 
observing program occupied the time of most of the staff for several 
months. The type of instrument adopted is a special form of the sen- 
sitive, quick-acting thermoelement which Mr. Clark has developed 
and used in many lines of research. Hight copies of this instrument, 
all automatically recording, were prepared under Mr. Clark’s direc- 
tion, and are now in successful operation at Camp Lee. Special glass 
filters, hemispherical in shape, are used to restrict the instrument to 
the measurement of radiation in known parts of the spectrum. De- 
scription of these instruments is given in a report soon to be issued. 
Dr. Abbot has continued his researches correlating solar activity 
with weather changes, and has published two articles on the subject 
during the year. 
Publication of Dr. Arctowski’s studies of terrestrial and solar at- 
mospheric circulation has been delayed. Dr. Arctowski has uncovered 
certain interesting phases of the subject which he feels require further 
study. 
Work in the field—Notwithstanding the continued handicap of 
manpower shortage, observations were made on every available day 
at all three field stations until February 1946. At that time the Tyrone 
station was closed because of the resignation of S. C. Warner as 
director. Since the sky conditions at Tyrone have been progressively 
less favorable during the past 4 years, probably owing to increased 
smoke and dust from mining operations in the general vicinity, the 
closing of this station is not too greatly regretted. At the end of the 
fiscal year arrangements were nearly completed to install the Tyrone 
equipment temporarily at a wet, sea-level location in Florida where 
valuable observations can be made concerning the transmission of 
radiation through water vapor and related problems. 
The program of observations of sun and sky radiation at Camp Lee, 
Va., begun in December 1945, is still in progress. The observations 
are made largely by personnel of the Quartermaster Board working 
under the direction of Mr. Hoover. ‘This has necessitated frequent 
trips by Mr. Hoover to Camp Lee to install, supervise, and inspect 
the work. From these Camp Lee measurements, a great volume of 
information is accumulating concerning the kind and amount of 
radiation, for each hour of each day, that falls upon the tents and 
exposed panels. These data will be summarized and published at 
intervals. The first report is expected to appear shortly. It is con- 
fidently hoped that these measurements will help to explain the causes 
of exposed fabric deterioration. 
