November 20, 1914] 



SCIENCE 



745 



membership of the association will be limited 

 to those who will be asked to attend this 

 meeting. The committee merely sought, by 

 the means indicated, to bring together a body 

 much larger and more representative than 

 itself, which may constitute a nucleus for the 

 association, and to whose judgment the com- 

 mittee may submit its recommendations. 



The committee is not empowered to define 

 authoritatively either the purposes or the 

 scope of the association, or the conditions for 

 membership in it. It is, however, to be ex- 

 pected that the association's future policy with 

 regard to these matters will be determined at 

 the meeting to be held nest month. 



Since the previous announcement of the 

 personnel of the committee, the following 

 members have been added to it: 

 G. B. Frankforter, 



University of Minnesota, 

 H. B. Mumford, 



University of Illinois, 

 C. E. Bessey, 



University of Nebraska, 

 Samuel B. Harding, 



University of Indiana, 

 Percy Bordwell, 



University of Iowa, 

 T. S. P. Tatloek, 



University of Michigan, 

 J. W. Garner, 



University of Illinois, 

 0. D. Adams, 



Dartmouth College. 

 The chairman of the committee, Professor 

 John Dewey, of Columbia University, or the 

 undersigned, will welcome suggestions from 

 any member of the university teaching pro- 

 fession relating to the plan of organization 

 and the future work of the proposed associa- 

 tion. 



Arthur O. Lovejot, 



Secretary 

 Baltimore, 



November 3, 1914 



ATMOSPHERIC OPTICAL PHENOMENA 



To THE Editor of Science : The letters from 

 Messrs. H. W. Farwell and A. W. Freeman, 



published in Science, October 23, 1914, pp. 

 595-596, are two of the many recent indica- 

 tions of the fact that more attention is now 

 being given than formerly to the observa- 

 tion of atmospheric-optical phenomena. The 

 meteor seen by Mr. Freeman was not, as he 

 supposes, a tertiary rainbow, but the circum- 

 zenithal arc of a solar halo. This particular 

 arc is also known as the upper quasi-tangent 

 arc of the halo of 46 degrees. 



The complex halo observed by Mr. Freemaa 

 at Fredericksburg, Va., November 2, 1913, 

 was visible, in various degrees of development, 

 on November 1 and 2, at a great number of 

 places throughout the eastern half of the 

 United States, and constituted the most re- 

 markable display of the kind heretofore re- 

 corded in this country. It should be noted 

 that the small arc, convex to the sun, marked 

 " rainbow " in Mr. Freeman's drawing, was 

 the same phenomenon as that observed by Mr. 

 Farwell, i. e., the oircumzenithal arc of a halo. 

 The term " rainbow " is highly inappropriate 

 for this or any other halo phenomenon. 



Mr. Freeman's observation is noteworthy on 

 account of including the rare phenomenon of 

 the anthelion — a white mock-sun directly oppo- 

 site the sun in azimuth, and at the same alti- 

 tude above the horizon. The large outer 

 circle, shown in the drawing, extending around 

 the horizon, is the parhelic circle, a well-known 

 though rather uncommon phenomenon. The 

 inner, partial circle, drawn parallel to this, is 

 decidedly unusual. It appears to be a second- 

 ary parhelic circle, produced by the upper 

 vertical parhelion of the 22-degree halo serving 

 as luminous source. This and other second- 

 ary halo phenomena produced by parhelia haye 

 been described by Bravais and Besson. 



The August number of the Monthly Weather 

 Review, which has just appeared, contains a 

 translation of a recent memoir by Besson de- 

 scribing all known forms of halo. No such 

 comprehensive account of these phenomena haa 

 heretofore been published in English. The 

 same number of the Review contains an exten- 

 sive report on the halos of November 1-2, 1913. 



C. FiTZHUGH TaLMAN 



U. 8. Weather Bureau 



