78 



The Irish Naturalist. 



NOTES. 



GEOLOGY. 



The Adare Meteorite. 



A shower of meteoric stones, the largest of which weighed 65 lbs. (29.5 

 kg.) fell near Adare, Co. Limerick, on September loth, 18 13. Two samples 

 are in the museum of Trinity College, Dublin (V. Ball, Jouvn. R. Geol. Soc. 

 Ireland, vol. vi., p. 160, 1882), and there is one, weighing 134.9 grammes, 

 in the National Museum. Dr. James Apjohn, in 1839, published an 

 elaborate account of the material from a chemical point of view (" Analysis 

 of a meteoric stone which fell near Adair, on September loth, 18 13," 

 Trans. R. Irish Acad., vol. xviii., p. 17). In addition to the iron and nickel, 

 he detected chromium and a little cobalt, and " a trace of oxide of man- 

 ganese " in the part undissolved in hydrochloric acid. From his final 

 results (p. 29) he concluded, acutely enough, that the matrix of the stone 

 consisted of a unisilicate, in which one atom of olivine was united with one 

 atom of pyroxene. In 1874, Richard Apjohn, m.a., t.c.d., Praelector of 

 Chemistry, Caius College, Cambridge, investigated one of the specimens 

 in Trinity College, Dublin, in connexion with his researches on the occur- 

 rence of vanadium (" On the analysis of a meteoric stone and the detection 

 of vanadium in it," Joiirn. Chem. Soc, New Series, vol. xii., p. 104). He 

 seems, curiously enough, to have been unaware of James Apjohn's publica- 

 tion thirty-five years before, though the veteran chemist was still living. 

 V. Ball, on the other hand [op. cit., p. 1 59), ignores Richard Apjohn's paper. 

 R. Apjohn gives the iron to nickel proportion as 85. 120 to 14. 275 per cent., 

 that is, 6 : I. He finds 6. 26 per cent, of manganese oxide in the portion of 

 the meteorite soluble in hydrochloric acid, and 8 . 84 in the insoluble portion. 

 Dr. G. T. Prior, f.r.s. {Min. Mag., vol. xviii., p. 33, 1916), on the basis 

 of R. Apjohn's figures, found the Adare stone to be somewhat anomalous 

 among chondrites, (which are the typical stony meteorites with diffused 

 blebs of nickel-iron). He was inclined to question the uniform distribution 

 in it of so high a percentage (19.07) of nickel-iron, and thought that its 

 richness in nickel allied it to his Baroti group. He has now, however (Min. 

 Mag., vol. xix., p. 167, 1921), analysed a fragment in the collection of the 

 British Museum. He shows that the large percentage of manganese deter- 

 mined by R. Apjohn should probably be referred to magnesia. He confirms 

 the high percentage of nickel-iron, but raises the proportion of iron to nickel 

 from. 6 to 11. These results seem, then, to place the Adare meteorite within 

 Prior's Cronstad group. He gives the mineral composition, from his 

 detailed analysis, as bronzite 33. 83, olivine 32. 64, nickel-iron (Fe : Ni =11) 

 18.46, felspar (mainly albite) 7.52, troilite 5.60, chromite 0.87, and 

 apatite 0.63 per cent. 



G. A. J. Cole. 



Royal College of Science, Dublin. 



