BrdW/i HiOhatitic Iron-ore. — Encke's Comet. ' 153 



he may still find some traces of conformity with other com- 

 pact meteoric iron. 



" The surface shows distinctly that it consisted of small frag- 

 ments of lighter and darker colours, which have been joined 

 together by an imperfect process of smelting ; and in some 

 may be seen the remains of its former octahedral form and 

 foliated texture. I tried a piece of about \\ inch square, by 

 laborious filing and tlie application of aqua-fortis, for the pui- 

 pose of discovering traces of the damasked crystalline figures; 

 but I could not find any, and indeed could scarcely expect any 

 after the process it had undergone. However, this surface 

 also shows that the iron consists of small fragments joined 

 together ; and some parallel small fissures show that the prin- 

 cipal surfaces of separation of the octahedrons were diagonal to 

 tlie greater surfaces of the specimen *. If I did not know, from 

 tlie account of Colonel Gibbs, and the preliminary analysis of 

 Prof Bischof, that this iron contains nickel, I should con- 

 clude so from its colour on the surface, which I polished and 

 treated with the acid. The circumstance of this colour being 

 of a darker gray than in other meteoric irons (that of the Cape 

 of Good Hope excepted), is probably occasioned by the mix- 

 ture of carbon in the smeltinff." 



BROWN HjEMATITIC IRON-OIIE FORMED AROUND CAST-IRON 

 PIPES. 



On examining a set of cast-iron pipes which had lain some 

 years in the line of one of the streets in the New Town of 

 Edinburgh, we were surprised to find the sand iu which they 

 had been laid, where in contact with the pipes, very compact 

 and brown in colour. On breaking some of the masses, we 

 found the connecting matter to be brown iron-ore, and in ca- 

 vities of the compacted sand this brown iron-ore exhibiting 

 that particular lustre approaching to adamantine, and the 

 reniform shape with the granulated surface of brown haematite. 

 Here, then, we have an instance of the formation, by the action 

 of percolating water on the iron of the pipes, of an ore of iron 

 which some observers ari'ange with the igneous mineral for- 

 mations. — Edin. Phil. Journ. 



THE RE-DXSCOVERY OF THE COMET OF ENCKE DUE TO MR. 

 RUMKER, AND NOT TO MR. DUNLOP. 



In a paper published in the Transactions of the Royal So- 

 ciety of Edinburgh, (vol. x. p. 112, 113,) by Sir Thomas 



• I should be inclined to consider these jjarallcl fissures rather as oblong 

 air-bubbles produced in the smelting, than as the remains of a former texture. 



— N(egf!^er(ith. 



V^ol. GG. No. 328. yi//-'. 1825. U Brisbane, 



