EEPORT OP THE SECRETABY 123 



$1,000 from the Research Corporation of New York. At the close of 

 the fiscal year the instrument was almost ready for use, having been 

 constructed by A. Kramer at the instrument shop of the Observatory. 



FIELD STATIONS 



In cooperation with Doctor Wulf, of the Fixed Nitrogen Research 

 Laboratory, of the Department of Agriculture, an investigation has 

 been carried through at Table Mountain, Calif., on the absorption of 

 well-determined quantities of ozone in the visible spectrum. In this 

 research, ozone-laden air contained in special absorption cells was 

 interposed before the slit of the spectrobolometer which records the 

 energy of the solar spectrum. A new, independent method of de- 

 termining the atmospheric ozone content was worked out and ap- 

 plied. Its results agree nearly with those determined by the method 

 of Dobson. 



The daily observation of the solar constant of radiation has been 

 carried on regularly at the three field stations: Table Mountain, 

 Calif. ; Montezuma, Chile ; and Mount Bruldcaros, Southwest Africa. 

 The latter station has been supported by grants from John A. 

 Roebling. Impressed by the probability of useful weather applica- 

 tions, Mr. Roebling has made a further grant to finance an expedi- 

 tion of a year's duration in Africa and outlying regions to endeavor 

 to find a site equal to Montezuma, Chile, for solar-radiation work. 

 Accompanied by Mrs. Moore, A. F. Moore, who has had long experi- 

 ence at our mountain observatories, occupied Fogo Island peak in 

 the Cape Verde Islands for several weeks, and is now in Southwest 

 Africa testing various high mountain sites in comparison with Mount 

 Brukkaros. 



A fire caused by a kerosene heater destroyed the computing room 

 at Montezuma station, with mathematical tables and instruments used 

 in the reductions. The observations suffered a few days of delay 

 before new tables could be sent, but no days were lost to the perma- 

 nent record of the station. 



PERSONNEL 



At Washington the personnel is unchanged since the last report, 

 except that Oliver Grant served as additional computer throughout 

 the 3^ear in the preparation of Volume V of the Annals. Also George 

 Cox served from November, 1930, on the reduction of ozone observa- 

 tions and other computing. Both young men were compensated from 

 the Roebling funds. 



C. P. Butler, formerly assistant at Montezuma, was placed in 

 charge of that station on January 11, 1931, vice H. H. Zodtner, trans- 

 ferred to Table Mountain to carry on there during the absence of 



