Henry Woodiuard — Address to the Geologists^ Association. 533 



obtained in a pure state, by which the entire constituents could be 

 determined in a single portion. The silica was removed by dis- 

 tillation with hydrofluoric acid, and afterwards estimated as fluosili- 

 cate of potassium. 



The Busti Aerolite, which fell on 2nd December, 1852, near 

 Goruckpur in India, was first examined, and found to consist of the 

 following minerals : — Oldliamite, or monosulphide of calcium, which 

 occurs in chestnut-brown nodules with cubic cleavage. This 

 mineral is not only unknown in terrestrial strata, but has been 

 for the first time met with in this meteorite. A body of such 

 unstable characters points to peculiar conditions (as suggested 

 already, by the occurrence of hydrogen in meteoric iron), imder 

 which meteoric minerals must have been formed. Osbornite is another 

 new mineral, occurring principally in the Oldliamite of this stone in 

 minute gold-coloured regular octahedra, but so very sparsely that 

 determination of its constitution was almost impossible. They 

 withstand. the action of most reagents, and appear to be a compound 

 of zirconium (or titanium) and calcium with sulphur and oxygen. 

 Augite, in intimate association with Oldhamite, crystallizing in the 

 oblique system, and exhibiting a remarkable dichroism of a pale 

 violet-grey colour, and with the composition (f Mg f Ca) Si O3. 

 Enstatite in three varieties : a dark-grey tabular, a transparent 

 white, and a semi-transparent grey, the crystallographic features 

 of which were not well developed. They had but a slight dif- 

 erence in composition, and bear the greatest reseinblance to the 

 mineral found by Dr. Lawrence Smith in the Bishopsville stone. 

 Nickeliferous iron, Troilite and Chromite in regular octahedra, are 

 also present, but in very small amount. 



The Manegaum Meteorite, which fell on the 29th June, 1843, at 

 Manegaum in Khandeish, was found to consist of a single pale 

 yellow-green silicate, the crystals and the- fine ground-mass, in which 

 they are inclosed, having the same composition : that of an Ensta- 

 tite with the formula (f Mg ^ Fe) Si 0^. A very small amount of 

 iron was also met with. This stone differed from that of Busti, in 

 that the latter contains a nearly pure magnesian Enstatite, that of 

 Manegaum being a highly ferriferous one. The two meteorites 

 concur in throwing light on the nature of the flocculent opaque 

 mineral seen in the microscopic sections of many meteorites. 



The Breitenbaoh Meteorite was found at Breitenbach, in 

 Bohemia, in 1861. It belongs to that class of meteorites which have 

 been termed " siderolites," a sponge-like skeleton of nickeliferous 

 iron inclosing silicates. The siliceous minerals in the present in- 

 stance are two in number : the one is a ferruginous enstatite or 

 bronzite, crystallizing in the rhombic system, and having the formula 

 (Mg±Fe-i-) SiOs; the other is a new form of silica, having the 

 specific gravity of fused quartz (2*24), and crystallizing in the ortho- 

 rhombic system, differing therefore in its system from the recently 

 discovered tridymite of Vom Eath. Asmanite, as the meteoric 

 silica has been named, constitutes almost one-third of the mass of 

 mixed siliceous minerals. Troilite and Chromite are also sparingly 



