209 



METEOROLOGY. 

 ON LUNAR AND PLANET ABY INFLUENCES OVER THE WEATHER. 



CONCLUDED. 



By the remarkable coincidence of magnetic and isothermal lines, 

 noticed in a former number of this Miscellany, we are led to recog- 

 nise the beautiful phenomenon of the aurora borealis as connected 

 with atmospheric changes. It seems highly probable that the 

 aurora is a reflex of terrestrial magnetism. The following principles 

 or facts corroborate this: — when in our climate the aurora borealis 

 is com})lete ; that is, when its permanent curvilinear light pictures on 

 space a well defined arch, the culminating (or central) point of this 

 arch is on the magnetic meridian, and its two points of apparent 

 intersection with the horizon are at equal angular distances from the 

 same meridian. Again, when it projects luminous and transient 

 columns from different portions of this arch, their point of intersection 

 (for they all tend towards one centre) is found to be on the magnetic 

 meridian, and precisely upon the point towards which the dipping 

 needle, indefinitely extended, is directed. It may here, incidentally, 

 be observed, that the aurora, like the rainbow, has no fixed locality, 

 being dependant entirely on the position of the observer for its 

 apparent place, as referred to the sidereal heavens ; the magnetic 

 meridian varying in every locality. Observations, that changes of 

 weather generally either follow or immediately precede the appear- 

 ance of a vivid aurora seems to be confirmatory of the theory of a 

 mutual but hitherto inexplicable association. 



The various instincts and habits of plants and animals, and other 

 indications of organic nature, afford signs by which approaching 

 changes of weather may be inferred. Some of these effects, espe- 

 cially in vegetables, are merely mechanical, and produced by different 

 degiees of saturation in tlie atmosphere ; others, possibly, are che- 

 mical and physiological ; but that an important class of distuibances 

 affecting organic nature on these occasions is the result of electric 

 action, is certain. This branch, then, of meteorological enquiry is 

 su.sccptiblo of vast acqui.sition from future and sensible re.seaich. 



c c 



