914 



THE BELL SYSTEM TECHNICAL JOURNAL, JULY 1956 



48 49 50 51 52 53 54 55 56 57 58 59 

 FREQUENCY IN KILOMEGACYCLES PER SECOND 



60 61 



Fig. 8 — Calculated and measured absorption by air at sea level. The dots 

 represent the experimental data; the vertical lines indicate the spread in the meas- 

 ured values. Curves A and B are calculated curves of oxygen absorption using 

 line-breadth constants of 600 and 1200 mc, respectively^, and a temperature of 

 293° K. (Courtesy of T. F. Rogers, Air Force Cambridge Research Center.) 



RESULTS 



The data to be discussed are shown in Fig. 8; they were taken at Hohn- 

 del, N. J., during the months of December, 1954, and January, 1955, on 

 days when the temperature was between 25 and 40 degrees Fahrenheit ; 

 the absolute humidity was less than 5 grams/meter^ during the measure- 

 ments. It is believed, therefore, that the resonance of the oxygen mole- 

 cule is the main contributor to the absorption. 



The spread in llie measurements is indicated by vertical lines through 

 the average values. Each point represents an average of six or more meas- 

 m'oments taken on different days. In the range 49 to 54.5 kmc, (5.5 to 



