METEOROLOGY. r>/ 



although it seems not improbable that they are impelled 

 from the lunar volcanoes. There are records of more 

 than 30O instances of Aeroliths of all sizes, from a few 

 ounces to some hundreds of pounds weight, falling in 

 different parts of the earth. They strike the earth 

 obliquely with a great force, penetrating it to a consi- 

 derable depth. An Aerolith of fifty-six pounds weight 

 fell in Yorkshire in 1795. Immense masses of iron of 

 a meteoric nature have been found in different parts of 

 the earth ; from a portion of a mass which was found 

 near the Cape of Good Hope, a sword was some years 

 since manufactured and presented to Alexander, the late 

 Emperor of Russia, by Mr. Sowerby, a gentleman then 

 well known in the scientific world, but since deceased. 



One of the most beautiful meteoric appearances is the 

 Aurora Borealis, which, though rarely seen in our lati- 

 tude, is a constant visitor of the Arctic regions : some- 

 times covering the whole heavens, and eclipsing by its 

 splendour the stars and planets. The Aurora Borealis 

 is often accompanied with a rustling snapping noise, and 

 its appearance has been described as terrifically grand. 

 There have been various opinions relative to the cause 

 of this phenomenon, but it is generally ascribed to the 

 combustion of inflammable air by means of electricity ; 

 although, from recent observations of the polar voyagers, 

 it appears to be in some way connected with the mag- 

 netism of the earth. 



The Ignis Futuus, or Jack with a Lantern, is a meteor 

 that is often seen in marshy places, and is supposed to 

 be of the nature of phosphuretted hydrogen gas. This 

 meteor is never seen on hills or other elevated places, 

 because they do not sufficiently abound with moisture 

 to produce this gas. 



When the air is put into motion through any cause, it 

 becomes Wind. The principal cause of Wind is the 

 rarefaction of the air through heat ; the rarefied air 

 ascending, the unrarefied rushes in to supply its place. 

 Evaporation is another cause of Wind, by producing an 

 increase of volume in the atmosphere ; and Rain is con- 

 sidered a third cause. Although the Wind in our climate 

 is considered very changeable and uncertain, yet even in 

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