ABSTRACTS 



Authors of scientific papers are requested to see that abstracts, preferably 

 prepared and signed by themselves, are forwarded promptly to the editors. Each 

 of the scientific bureaus in Washington has a representative authorized to for- 

 ward such material to this journal and abstracts of official publications should 

 be transmitted thru the representative of the bureau in which they originate. 

 The abstracts should conform in length and general style to those appearing in 

 this issue. 



PHYSICS. — The determination of aqueous vapor above Mount Wilson. 

 F. E. FowLE. Astrophysical Journal, 36: 359. 1913. 



The quantity of precipitable water existing in the form of vapor be- 

 tween the top of Mount Wilson and the outer hmits of our atmosphere 

 during fair weather from June to November, 1910, and 1911, was deter- 

 mined by the spectrobolometric method described in detail in the Astro- 

 physical Journal, 35: 149. 1912 (see this journal, 2:318. 1912). The 

 average quantity present was 0.69 cm. and the range from 0.2 cm. to 

 about 2.8 cm. of precipital)Ie water. The difference in the monthly 

 means would be small but for a few exceptionally moist days in August; 

 almost the dryest day indeed for 1910 was August 13 (0.17 cm.) and the 

 dryest for 1911, September 12 (0.12 cm.). A gradual but generally 

 slow increase in atmospheric water vapor often took place during the 

 observations which extended from about 7 a.m. to 10 a.m. This averaged 

 0.12 cm. For about 40 per cent of the days this increase was less than 

 0.1 cm. 



These spectrobolometric results were then used in a study of the 

 formula of Hann which, with a coefficient determined from balloon and 

 kite observations, has been in use for connecting surface humidities 

 with the quantity of aqueous vapor in the atmosphere. This coefficient 

 was redetermined by means of the data above discussed. The general 

 mean for the coefficients (1.8) agrees closely with that derived by Hann 

 (1.9), also with that from Humphrey's data (1.7). The range of values 

 is, however, so great (from 0.33 to 11.80) that we must regard the for- 

 mula, though applicable for mean conditions, as of no value for individ- 

 ual days. F. E. F, 



425 



