Intelligence and Miscellaneous Articles. 151 



CARBURET OF SULPHUR NOT DECOMPOSED BY ELECTRICITY. 



According to M. Wohler, the black deposit on the sides of the 

 tubes, which M. Becquerel supposed to be carbon derived from the 

 decomposition of carburet of sulphur by electricity, is merely sulphuret 

 of copper produced from the sulphur in the sulphuret of carbon. 

 Poggendorf's Annalen. Brf.wster's Journal, Jan. 1831. 



INFLUENCE OF THE AURORA BOREALIS ON THE MAGNETIC 

 NEEDLE. 



Mr. Sturgeon has mentioned, in his paper on the Aurora Borealis 

 of Jan. 7th, as witnessed at Woolwich (p. 128 of our present Number), 

 that he could not observe the slightest change of direction or disturb- 

 ance in the magnetic needle, during the display of the Aurora. As 

 this is a subject of much importance, we deem it improper to publish 

 this result, without stating, at the same time, that M. Arago, at the 

 Observatory of Paris, was also engaged on the evening of the 7th, in 

 observations on both the horizontal and the dipping-needle, during 

 the appearance of the Aurora ; and that he found the former to be de- 

 ranged 1 6' 47" by the influence of that meteor, and the latter the 

 enormous quantity of 21', the ordinary diurnal variation of the dip, at 

 this season, scarcely exceeding 1 '. An account of M. Arago's ob- 

 servations will be found in the Le National of January 12th. 



NITROUS ATMOSPHERE OF TIRHOOT. 



Tirhoot is one of the principal districts in India for the manufacture 

 of saltpetre ; the soil is everywhere abundantly impregnated with this 

 substance, and it floats in the atmosphere in such quantities, that 

 during the rains and cold weather it is attracted from thence by 

 the lime on the damp walls of houses, and fixes there in shape of 

 long downy crystals of exceeding delicacy. From damp spots it may 

 be brushed off every two or three days almost in basketsful. In con- 

 sequence of all this, the ground, even in hot weather, is so damp, 

 that it is extremely difficult either to get earth of sufficient tenacity 

 to make bricks (the country being quite destitute of stones), or, 

 when made, to find a spot sufficiently solid to sustain the weight of 

 a house. Even with the greatest care the ground at last yields, and 

 the saltpetre corrodes the best of the bricks to such a degree, that the 

 whole house gradually sinks several inches below its original level. 

 Houses built of inferior materials of course suffer much more ; one, 

 of which the inner foundations were of unburnt bricks, absolutely 

 fell down whilst I was at Mullye, and the family in it escaped almost 

 by miracle. My own house, which was not much better, sank so 

 much, and the walls at bottom so evidently giving way, that I was 

 compelled with extreme expense and inconvenience, to pull down 

 the whole inner walls, and build them afresh in a more secure man- 

 ner. From the same cause a new magazine which Government di- 

 rected to be built, with an arched roof of brick-work, was, when 

 complete, found so very unsafe, that it was necessary to demolish 

 it entirely, and rebuild it on a new plan, with a roof of tiles. In such 

 a soil it will easily be concluded that swamps and lagoons prevail 



very 



