370 



SCIENTIFIC RECORD FOR 1884. 



359. A. Paulseu, of Copenbageu, gives iu Nature, xxix, p. 337, the 

 results of observation ou the height of the aurora as made at Godthaab, 

 of which tlie following notice appears in the Aus:«trian Zeitschrift far 

 Meteorologic : 



The results of observations at that station on the altitude of auroras 

 were as follows : 



Of the latter 14 cases the lowest were, respectively, 3.72, 3.69, 3.22, 

 2.87, 1.99, 1.96, 1.35, 0.61. 



360. Prof. H. Fritz, of Zurich, states that as these observations were 

 very carefully made, the distance between the two observers being 5.8 

 kilometers, they seem especially worthy of study, and undoubtedly 

 coufirm the observations of S. Fritz, made at Ivigtut, and those of 

 Steenstrup, made in Iceland, and assure us that undoubtedly the 

 auroral light may exist even at the ground. He has therefore at once 

 collated all previous records of low-lying auroras, and makes some 

 general remarks upon the present state of our knowledge with regard 

 to these and the character of the observations still needed to further 

 elucidate the subject. {Z. 0. G. M., xix, p. 290.) 



361. Prof. H. Fritz, in a general review of Tromholt's IS^ordlysets 

 Perioder and of Eubeuson's Catalogue of Swedish Auroras, finds that 

 the 111-year period, first determined by him in 1862 and confirmed by 

 Loomis for the American auroras, is also strongly confirmed by Eubeu- 

 son's catalogue. He also finds that the influence of the bright light of 

 the moon in introducing an apparent lunar period, as first shown by him 

 in 1864, is fully confirmed by Tromh<:)lt from the study of observations 

 at Godthaab and Christiauia. {Z. 0. G. 717., xviii, p. 321 ) 



362. Prof. Sophus Tromholt, in his " Om jS^ordlysets Perioder," pub- 

 lished by the histitut Met. Danois, deduces the following conclusions 

 from the observations of the aurora made at Godthaab, in Greenland, 

 during 1865 to 1880 by Professor Kleinschmidt : 



1. Everything pertaining to the va'iable frequency of auroras in 

 Godthaab jiroves that the phenomenon exists there under quite different 

 conditions from those obtaining in lower latitudes. 



2. The number of observed auroras is inversely proportional to the 

 square root of the cloudiness. 



3. After correcting for cloudiness there remains not only no parallel- 

 ism between the .sun-spots and the auroras, but even an almost diamet- 

 rical difference as to frequency. 



4. The maximum of auroras is delayed two years behind the minimum 



