PROCEEDINGS OF THE ACADEMY AND AFFILIATED 



SOCIETIES 



THE PHILOSOPHICAL SOCIETY OF WASHINGTON 



The 704th meeting was held on February 10, 1912. Two papers were 

 read: Constancy of wire resistance standards: Frank Wenner, of the 

 Bureau of Standards. To appear in this Journal. 



The Measurement of inaccessible displacements, the production of tem- 

 perature uniformity , and the determination of the expansion of gas ther- 

 mometer bulbs: A. W. Gray, of the Bureau of Standards. To appear 

 in this Journal. 



The 705th meeting of the Society was held on February 24, 1912. Two 

 papers were read. The nitrogen scale between 800° and 600°, and a new 

 determination of the boiling point of sulphur: A. L. Day and R. B. Sos- 

 man, of the Geophysical Laboratory. See this Journal 2: 167. 1912. 



Comparison of the nitrogen and platinum resistance scale between 300° 

 and 600°: H. C. Dickinson and E. F. Mueller, of the Bureau of 

 Standards. See this Journal 2: 176. 1912. 



The 706th meeting was held on March, 9, 1912. Two papers were 

 read: Experiments on the light of the sky: C. G. Abbot, of the Smiths- 

 onian Institution. This paper gave an outline of progress in a research 

 on the quantity and distribution of the solar radiation received indirectly 

 by diffuse reflection from the sky. Preliminary experiments were begun 

 in 1905 on Mt. Wilson and were continued in 1906. Further experiments 

 were made at Flint Island in 1907, and in 1910 on Mt. Whitney with 

 new and improved apparatus. The relative brightness of the sky with 

 reference to zenith distance and to distance from the sun was given. The 

 total quantity of indirect solar radiation, as compared with the direct, 

 proved to be about seven per cent for Mt. Whitney (4420 meters ele- 

 vation) at high sun. By adding the observed direct radiation on Mt. 

 Whitney (1.71 calories per square centimeter per minute), the indirect 

 (0.12), and that absorbed by water vapor (0.04) the va'ue 1.87 calories 

 was reached This was less (as it ought to be) than the intensity found for 

 the solar radiation outside the atmosphere at the sun's actual distance 

 on the day of observation. This latter value was 2.00 calories. 



On the formation of the solar corona, and the total solar eclipse of October 

 10-12, 1912: L. A. Bauer, of the Carnegie Institution of Washington. 

 The speaker gave a preliminary summary of the general observat ons 

 thus far made regarding the formation of the solar corona and the varia- 

 tions exhibited during the sun-spot cycle. Lantern-slides were given in 

 illustration. It would appear that some force, in addition to the explo- 

 sive forces and the repellant action of the pressure of light, of an electric 

 or magnetic nature, is necessary to explain the curvatures of the coronal 

 streamers, as has already been pointed out by various investigators. 

 Thus a detailed and persistent study of the solar corona may throw light 

 on the question of the magnetization of the sun itself. The subject 



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