584 COSMOS. 



shooting-stars darting across this region maintained their 

 white colour unaltered, whence it may be inferred that the 

 northern light was further removed from the surface of the 

 Earth than the shooting-stars were at that point where they 

 became invisible. (Schum. Astr. Nadir, no. 372, p. 78.) The 

 relative velocity of shooting-stars has hitherto been estimated 

 at from 18 to 36 geographical miles a second, while the Earth 

 has only a translatory velocity of 16'4 miles. (Cosmos, vol. i. p. 

 107 and note). Corresponding observations of Julius Schmidt 

 at Bonn, and Heis at Aix-la-Chapelle (1849), gave as the 

 actual minimum for a shooting-star, which stood 48 miles 

 vertically above St. Goar, and shot over the Lake of Laach 

 only 14 miles. According to other comparisons of the same 

 observer, and of Houzeau in Mons, the velocity of four 

 shooting-stars was found to be between 46 and 95 miles in 

 the second, consequently two to five times as great as the 

 planetary velocity of the Earth. The cosmical origin is 

 indeed most strongly proved by this result, together with the 

 constancy of the simple or multiple points of divergence, i. e. 

 together with the circumstance, that periodic shooting-stars, 

 independently of the rotation of the Earth, proceed during 

 several hours from the same star, even when this star is not 

 that towards which the Earth is moving at the same time. 

 According to the existing measurements, fire-balls appear to 

 move slower than shooting-stars ; but it nevertheless remains 

 striking that when the former meteors fall, they sink such a 

 little way into the ground. The mass at Ensisheim in Alsace 

 weighing 276 pounds (November 7th, 1492), penetrated only 

 3 feet, and the aerolite of Braunau (July 14th, 1847) to the 

 same depth. I know of only two meteoric stones which have 

 ploughed up the loose earth for 6 and 18 feet; these are 

 the aerolites of Castrovillari, in the Abruzzi (February 9th, 

 1583), and that of Hradschina in the Agram district (May 

 6th, 1751). 



