SECRETARY’S REPORT 123 
Dr. Abbot, research associate of the Observatory, has made further 
contributions in his studies of relationships between solar changes and 
weather (see list of publications below). Mr. Hildt, mentioned in 
last year’s report as assisting Dr. Arctowski in his researches concerned 
with the solar and terrestrial atmospheres, found it necessary to end 
this work on October 1, 1947. Miss Joyce Wilson substituted for Mr. 
Hildt for the remainder of the fiscal year. 
Work in the field.—Regular observations for the determination of 
the solar constant were continued throughout the year at two high- 
altitude stations, Montezuma, Chile (9,000 ft.) and Table Mountain, 
Calif. (7,500 ft.). In addition, at Montezuma preparations were made 
for exposures of certain textiles and observations of the amount and 
quality of sun and sky light, similar to the work now in progress at the 
Miami station. However, unexpected delay was encountered in the 
transfer of part of the equipment to Montezuma, so that these ex- 
posures and observations had not yet been started at the close of the 
fiscal year. 
As stated in last year’s report, a cooperative program was arranged 
between the General Motors Corp., the Quartermaster Department, 
and the Smithsonian Institution for exposures and radiatiton measure- 
ments to be carried out at the General Motors Test Field at Miami, 
Fla. The program also included the mounting and servicing of the 
panels and filter boxes by the South Florida Test Service, under the 
direction of E. M. DeNoon. In November 1947, panel exposures both 
in the open and under filters, at an angle of 45° to the south, were 
begun at Miami. The measuring instruments and the filters are 
similar to those used at Camp Lee, Va. In addition, the spectrobo- 
lometer formerly at the Tyrone, N. Mex., station has been mounted and 
adjusted. Whenever the sky is sufficiently clear of clouds, bolographs 
are taken just as in our usual solar-constant program. From these 
bolographs we obtain valuable data concerning sea-level water-vapor 
conditions, as well as additional data on the relative distribution of 
energy throughout the spectrum as received from direct sunlight. The 
complete program was started in December 1947. 
In July 1947 the Director began a tcur in search of the most promis- 
ing high-altitude site to which to transfer the Miami spectrobolomet- 
ric equipment at the conclusion of our sea-level observations. It was 
thought that possibly somewhere in the high plateau region of 
Mexico sufficiently cloudless and pure skies might be found. With 
the cordial cooperation of the staff of the National Observatory of 
Mexico, at Tacubaya, many records of sky conditions were examined 
and several promising sites were visited. It is regretted that though 
the climate was uniformly delightful and invigorating, none of these 
sites proved to be sufficiently cloudless. Floating clouds are very 
prevalent. 
