434 SPECIAL RESULTS IN THE URANOLOGICAL 



4 geographical miles of the level of the sea. On the other 

 hand, Heis remarks that, by exact calculation, a shooting 

 star seen on the 10th of July, 1837, simultaneously at Ber- 

 lin and at Breslau, shone out first at an elevation of 62 

 German, or 248 English miles, and disappeared at the 

 height of 42 German, or 168 English miles : other 

 shooting stars, on the same night, vanished at the height of 

 56 English geographical miles. Prom the older investiga- 

 tion of Brandes (1823), it followed that out of 100 shooting 

 stars seen and well measured from two stations, 4 had an 

 elevation of only from 4 to 12 English geographical miles, 

 15 between 12 and 24; 22 between 24 and 40; 35 (about 

 one-third of the whole number) between 40 and 60 ; 13 

 between 60 and 80; and only 11 (about one in ten of the 

 whole) above 80, these being, indeed, mostly between 180 

 and 240 English geographical miles. The inferences in 

 respect to the colour of shooting stars, derived from a col- 

 lection of 4000 observations, extending over 9 years, were : 

 that "* are white, -f yellow, T y orange, and only ^ green." 



Olbers remarked that, at Bremen, during the fall of me- 

 teors in the night of the 12th 13th November, 1838, there 

 was a fine Aurora Borealis, which covered a large portion of 

 the heavens with a vivid blood-red light ; and that the falling 

 stars which shot across this region preserved their whiteness 

 unimpaired. Hence it may be inferred that the beams of 

 the Aurora were further from the Earth than the shooting 

 stars, when these last became invisible in their fall (Schum. 

 Astr. Nachr. No. 372, S. 178). * 



The relative velocity of motion of shooting stars has 

 hitherto been estimated at from 4J to 9 German, or 18 to 

 36 English geographical miles in a second ; while the Earth 



