iii 1908, whose winter quarters were located only a few miles from the main quarters 

 of the present Expedition at Cape Evans, states most definitely that the aurorae 

 observed at Cape Adare in 191 1 were very much brighter than those seen on the previous 

 Expedition in 1908. 



Not only was the brightness of the Cape Adare aurora greater than that observed 

 at Cape Evans, but also the number of occasions on which aurora was observed, 

 taking due account of the fact that observations were only made every second hour 

 at Cape Adare. It is, in fact, estimated that aurora? were seen on 64 per cent, of the 

 possible occasions, i.e. on about two in three observations when the meteorological 

 conditions were favourable, corresponding with one in three (about) in the case of the 

 Cape Evans observations. 



Apart from this, Cape Adare did not suffer very seriously in 1911 from bad 

 weather. The Cape Adare observations are, therefore, a most valuable check on those 

 taken at Cape Evans, besides providing a great deal of independent data. 



Of the 398 occasions during the whole period of observation, where a note is made 

 of the brightness of the aurora 



69 are logged as " bright." 



93 ,, ,, " average brightness or above." 



170 ,, " average brightness or below." 



66 " faint." 



During the period May 26th to July 31st, aurora? were observed at the even hours 

 on 232 occasions. As was the case at Cape Evans, a large number of arches was 

 observed at an altitude of 70 or over in all, on 69 occasions. 



During the same period (taking all observations), aurora? were seen at altitudes of 

 70 or over on 148 occasions, glows being recorded on 122 occasions and colour mentioned 

 on 153 occasions. 



The frequent occurrence of aurora? at high altitudes and the large number of 

 occasions on which definite mention is made of coloured aurora? form a complete 

 antithesis to the Cape Evans observations. 



3. SHORT PERIOD VARIATIONS AND PERIOD CHARACTER OF THE AURORA. 



There is no evidence to show that aurora? as viewed from Cape Adare were more 

 variable in character, or in intensity, than the aurora? seen at Cape Evans, the same 

 tendency to variation being equally strong at both stations, so far as can be judged. 



There was a tendency also at Cape Adare for auroral displays to continue for 

 hours at a time, and sometimes even for days, though this tendency did not appear 

 to be so marked at Cape Adare as at Cape Evans. It may, however, be that the 

 difference between the two stations in this regard is due largely to the fact that 

 the presence of moonlight did not affect the aurora observations at Cape Adare to 

 the same extent as at Cape Evans. 



21 B 3 



