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CARNEGIE INSTITUTION OF WASHINGTON. 



at different distances from the optical axis of the microscope. In this way 

 curves were obtained which represent the distribution of Hght in the corona 

 at various distances from the limb. With this apparatus streamers and 

 details in the outer corona can be traced to points beyond that at which they 

 can be seen on the photographs. A nearly linear relationship is found to hold 

 for the law of darkening of the image along the fainter portions of the corona, 

 but in the bright streamers the rate of darkening increases rapidly £is the inner 

 corona is approached. The expression of these measures in terms of lumi- 

 nosity and the corrections to be appUed are being investigated. 



RESEARCHES ON STARS AND NEBUL/E. 

 OBSERVING CONDITIONS. 



The winter season of 1921-22 surpassed all records since the establishment 

 of the Observatory in the amount of precipitation. For the year ending 

 August 31 this reached a total of 60.5 inches, which is about 75 per cent above 

 the normal. In a single storm, December 17-26, the precipitation amounted 

 to 29.38 inches. The total snowfall for the year was 84 inches. The mean 

 temperature was 56° F., the maximum 95° on July 5, and the minimum 15* 

 on December 19. The average wind velocity was 10.3 miles an hour, with a 

 maximum on December 21 of 80 miles an hour. 



Owing to the exceptional amount of cloudiness and the atmospheric dis- 

 turbances accompanying the frequent storms, the observing conditions for 

 the 3''ear were somewhat below the normal, both as regards clearness of sky 

 and seeing. The 60-inch reflector was used during the whole of 193 nights 

 and during parts of 84 nights. These were distributed as follows: 



Observing record of 60-inch reflector. 



