November 17, 1916] 



SCIENCE 



717 



We shall not attempt to describe the Maya 

 chronology. It is a complicated and highly de- 

 veloped system. The larger part of Morley's 

 book is devoted to the description of it. His 

 exposition is admirably clear. No specimens 

 of Maya computation are extant. Maya 

 records contain only the results of computa- 

 tion. It is evident that considerable reckon- 

 ing is involved in Maya chronology. The 

 Maya had a sacred year of 260 days, an official 

 year of 360 days and a solar year of 365 -)- 

 days. The fact that 360 = 18 X 20 seems to 

 account for the break in the vigesimal system, 

 making 18 (rather than 20) uinals equal to 

 1 tun. Apparently, the Maya found the 

 lowest common multiple of 260 and 365, or 

 18,980. In their calendar 18,980 days eon- 

 situted the " Calendar Round," a period of 

 52 years which is " the most important period 

 of Maya chronology." Using this period, the 

 Maya developed an elaborate system of count- 

 ing time, " wherein any date of the Calendar 

 Round could be fixed with absolute certainty 

 within a period of 374,400 years." 



Florian Cajoei 



Colorado College, 

 Colorado Springs, Colo. 



SPECIAL ARTICLES 



THE FOCUS OF THE AURORAL STREAMERS ON 



AUGUST 26, 1916 



In a recent number of Science 1 the remark- 

 able auroral display of August 26 was de- 

 scribed by Professor C. C. Nutting, as ob- 

 served by him at Lake Douglas in northern 

 Michigan. The phenomenon was reported to 

 have been of unusual intensity and beauty. 

 The appearance of streamers in the southern 

 sky was particularly noted, as well as the fact 

 that the auroral glow prevailed around the 

 entire vault of the heavens, causing the earth 

 to be illuminated without shadows. 



This aurora was widespread because it was 

 also seen in northern New York, in New 

 Hampshire, in Nova Scotia, and over the Gulf 

 of St. Lawrence. According to a letter in the 

 current issue of Science, 2 it was observed as 

 far south as Martha's Yineyard, Mass. In 



1 N. S., Vol. XLIV, October 6, 1916. 

 2N. S., Vol. XLIV., October 20, 1916. 



each case the characteristics so well described 

 by Professor Nutting were observed. 



It has been reported as far west as Washta, 

 la., by F. S. Carrington. 3 In this case the 

 streamers in the northeast passed to the south 

 of the zenith, and the glow in the southern 

 horizon reached to about 30°. 



The aurora evidently extended eastward to 

 the British Isles, because a bright display was 

 reported by Mr. W. F. Denning at Bristol, 

 England, from 2 to 4 a.m., August 27. The 

 streamers were observed to an altitude of 70° 

 in the northern sky, and moved rapidly from 

 west to east. 4 



It was seen at Eskdalemuir, Dumfriesshire, 

 from 9 p.m., August 26, to past midnight, ac- 

 companied by considerable disturbance of the 

 magnets at the Kew Observatory. The mag- 

 netic storm commenced suddenly at 7 :45 p.m., 

 August 26. It was observed at Seskin, Water- 

 ford, in Ireland, from 10 :05 to 10 :40 p.m., 

 August 26, the streamers in the northern sky 

 stretching to within 20° or 30° of the zenith. 5 



The aurora was seen on the north shore of 

 Prince Edward Island by the writer, who noted 

 some of its interesting features; among which 

 was the location of the apparent focus of the 

 auroral streamers with respect to some readily 

 identified stars. To this particular attention 

 was paid. 



general features of the aurora 

 The writer was on a wide stretch of water 

 and observed the beginning of the aurora, 

 which occurred at 8 :15 p.m. Atlantic time, the 

 sky being perfectly clear. The glow at first 

 showed dimly in the southern sky, but rapidly 

 increased in intensity until the entire south- 

 ern portion of the vault of the heavens was 

 pierced by pale greenish lance-like streamers. 

 Those overhead terminated in a well defined 

 focus, southeast of the zenith, as shown in 

 Fig. 1. 



For some minutes there was no evidence 

 whatever of an aurora to the north. Later, 

 streamers rose in that section, and soon the 



3 The Guide to Nature, November, 1916, p. 191. 

 * Nature, Vol. 97, 2444, August 31, 1916. 

 5 Nature, Vol. 98, 2447, September 21, 1916. 



