METEOROLOGY AND ALLIED SUBJECTS. 



311 



must uiuloubtedly be considered as the carrier or agent of the aurora 

 phenomena. Weber and Kleiu and others give other data to show 

 the connection between the aurora and cirrus, such as, that the times of 

 greatest frequency of auroras and sun spots are also the times of great- 

 est frequency of the polar bands. 



There is also intimate connection between halos and other optical 

 phenomena and the cirrus. Observations of this character have been 

 discussed by Sophus Tromholt, of Norway, who finds for lirortheastern 

 Europe the following results : 



The parallelism bet\veen every form of atmospheric phenomena and 

 the record of solar spots shows the connection to be a real one, although 

 the rationale of the connection is not yet made clear. 



Further elaboration of this study shows that similar parallelisms 

 connect the sun spots with the rainfall, the heights of rivers, volcanic 

 eruptions, earthquakes, and numerous other phenomena. 



(20) The tenth chapter deals with the influence of the moon upon the 

 aurora. Scarcely a single terrestrial phenomenon, but what the attempt 

 has been made to connect it with the moon; and this is equally true of 

 the auroras. Thus Cotte, in 1780, seemed to show that there was an 

 excess of auroras when the moon is south of the equator as compared 

 with the time when she was north of the equator. Ualton, in 1834, 

 found the time of the greatest frequency of auroras to be at the time 

 of the changes of the moon. Richardson and Franklin, in the northern 

 part of British America, observed that the auroras were distributed 

 less frequently in the interval between the first quarter and full moon, 

 as compared with the latter half of the moon's orbit, in the ratio of 38 

 to 125. Broun, at Makerstoun, found the maximum frequency of 

 auroras to occur between the 18th and 22d day of the moon's age. 

 Fritz, himself, has investigated the distribution of over two thousand 

 auroras occurring between 1812 and 1860; he finds the influence of the 

 moon on the aurora to be very slight, and that the evidence thereof is 

 obscured by the effect of the relative brightness of the earth as illu- 

 minated by the moon. Hoslen, 1784, made a nineteen-year series of 



