Scientific Intelligence — Meteorology. 179 



send out rather a large reflector, and let him establish it on the Nil- 

 gherry hills, at a height of 6000 feet above the sea. But this re- 

 quest, which must have resulted in so much scientific credit for the 

 Company, was refused on the score of — expense. Then he offered 

 to make the telescope there at a cost of not more than the small sum 

 (insignificant when the result is considered) of £600, but this was 

 refused. 



He has, therefore, now begun making a 20-feet reflector at his 

 own private expense, and all he asks of the Company is to let him 

 establish it, with a part of the assistants of the Madras Observatory, 

 on the above-mentioned hills; and if this be refused, he is so strongly 

 impressed with the rich results that must inevitably follow the plac- 

 ing of one of the modern British reflectors on so favourable a geogra- 

 phical position of the Nilgherry hills, that he is determined, in such 

 a case, to throw up his appointment, and establish the telescope on 

 the heights himself, looking to support himself and family meanwhile 

 by coffee or indigo planting, or anything else which the climate and 

 soil of the country may allow. 



SCIENTIFIC INTELLIGENCE. 



METEOROLOGY. 

 L New Theory of Polar Lights. — Mairan, and, more lately, 

 Dalton, have explained this phase of the aurora by a hypothesis of 

 polar beams, long fiery rods of solar atmosphere, according to the 

 one, of red-hot ferruginous particles, according to the other, seen in 

 perspective, as they lie in the direction of the magnetic force. A 

 little acquaintance with the phenomenon — ^the rushing and tilting of 

 the beams against each other, one beam occasionally rising from the 

 horizon, passing through the centre of the crown and beyond it — 

 would shew the improbability of this hypothesis. I am persuaded, 

 that the phenomenon of the corona borealis is produced in a narrow 

 horizontal stratum of the earth's atmosphere. Thanks to the dis- 

 coveries of Dr Faraday, we do not require a ferruginous sea, in order 

 to have polarized particles ; the watery crystals that inhabit the up- 

 per regions of the atmosphere can themselves assume a polar state, 

 determined by the passage of electric currents ; and we have only to 

 complete this fact by a hypothesis of luminous electric discharges seen 

 refracted by these crystals, the position of visibility of the refracted 

 rays depending on the angles of the crystals, and the deflections from 

 the direction of the magnetic force which they suffer, by the electric 

 currents. Such an hypothesis, which occurs at once when an optical 

 phenomenon has to be accounted for, would explain these remarkable 

 auroral clouds, so often seen in connection with the aurora itself ; 

 it would also serve to explain the appearance of the arch at certain 

 altitudes, lower for lower altitudes, determined by the position of the 

 source of light, direction of the magnetic force at the place, and the 



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