539 ] 



XXXVIII. 



SOLAE HALOS SEEN AT GREYSTONES, CO. WICKLOW, ON 

 SEPTEMBER 22nd, 1S79 ; AND IN TEXAS AND OHIO, U.S.A., 

 ON OCTOBER 3rd, 1917. 



By SIR JOHN MOORE, M.A., M.D., D.Sc, F.R. Met. Soc. 



(Plate L.) 



[Read Apuil 23, 1913. Published April 16, 1919.] 



Through the courtesy of Mr. Charles P. Marvin, Chief of the Weather 

 Bureau of the United States Department of Agriculture, I am favoured 

 with a copy of the Monthly Weather Review, published by that great 

 organization, prepared and printed entirely within the Meteorological Office 

 at Washington, D.C. Each number of the Review contains a number of 

 contributions on climatology. Since August, 1915, the material for its pages 

 has been prepared and classified in accordance with the following sections : — 

 Aerology, General Meteorology, Forecasts, and General Conditions of the 

 Atmosphere, Rivers and Floods, Seismology, Bibliography, and Weather of 

 the Month. 



In the number of the Review for October, 1917 (vol. xlv, No. 10, 

 p. 486), I came across the following account of a remarkable complex series 

 of solar halos, which were seen at Houston, Texas, on the forenoon of 

 October 3rd, 1917. Some hours later a modified form of the same phe- 

 nomena appeared at Gallia, Ohio, about 1,000 miles, as the crow flies, to 

 the north-east of Houston. At the time that these halos were developed a 

 system of relatively low atmospheric pressure was crossing the United States 

 from the Rocky Mountain region, at first in a south-easterly direction,. 

 afterwards directly eastwards, and finally north-eastwards. This was exactly 

 the condition which would predispose to the formation of halos in a thin veil 

 of cirriform cloud suspended at an unusual height in the "free air," and 

 consisting of prismatic ice-crystals : — 



" Houston, Texas. — The following notes and sketch [PI. L., fig. 1] of a.' 

 solar halo observed at Houston, Tex., on October 3rd, 1917, are furnished by 



SCIENT. PKOC. K.D.S., VOL. XV., NO. XXXVIII. i P 



