1852.] On Bust Whirlwinds and Cyclones. 147 



fall, than the action of the battery became quieter, until the hissing 

 sound ceased, and the magnet again began to revolve : sparks of 

 course passed, and shortly the magnet revolved as quickly as it did 

 previous to the storm. 



" I mentioned the circumstance to my cousin Colonel Wilson, astro- 

 nomer at Lucknow, and asked him if he had ever seen a similar cir- 

 cumstance mentioned ; or, if he had ever observed his magnets in the 

 magnetic observatory at Lucknow in any way affected during the 

 passage of a dust storm. He replied he had not, and could not 

 account for it in any way. Query. Is there any point in the track of 

 these dust storms, (which are undoubtedly of the nature of Cyclones) 

 in which, if a magnet happened to be, it would lose its polarity for 

 the time, ceasing to be a magnet 1 



" If so, the cause would be clear. This did not strike me at the 

 time, or I might have easily tested it. 



" I recollect another phenomenon observed in one of these storms. 

 It occurred during the march of my Regiment up-country to join the 

 army of the Punjaub. We had left our ground long before day-light, 

 and were caught in a dust storm, followed by very heavy rain and 

 vivid lightning ; when the rain fell, the muzzles of the men's muskets, 

 and the peaks of the officers' caps, were seen tipped with that well 

 known electrical appearance, called St. Elmo's light : and this appear- 

 ance continued for some minutes, a quarter of an hour perhaps. I am 

 not quite sure now, whether I ought not to say, the tips of the Bayo- 

 nets, and not, the muzzles ; as we were marching with treasure, and, 

 I think, Bayonets fixed." 



2. — In Noad's Lectures on Electricity, page 337, the following pas- 

 sage occurs. 



"Dr. Dalton, in a work published in 1/93, has advanced several 

 ingenious hypothetical views respecting the cause of the Aurora, and 

 its magnetic influence. He says, 



" * We are under the necessity of considering the beams of the Aurora 

 borealis of a ferruginous nature, because nothing else is known to be 

 magnetic ; and consequently that there exists in the higher region of 

 the atmosphere, an electric fluid partaking of the properties of iron, 

 or rather of magnetic steel; and that this fluid, doubtless from its 

 magnetic property, assumes the form of cylindrical beams.' " 



v 2 



