Bradley — Composition of the Mineral Warwickite. 179 



Art. XI. — On the Analysis and Chemical Composition of 

 the Mineral Warwickite; by W. M. Bradley. 



Historical. — The mineral warwickite was first described by 

 Shepard* in 1838 and again more fully in 1839 ; in the latter 

 article he describes his method of analysis. Shepard named 

 the new species warwickite, after the original locality, War- 

 wick, Orange Co., JN\ Y. The mineral was found in limited 

 quantity as small, slender crystals, imbedded in a highly crys- 

 talline white limestone. It had earlier been called hypersthene 

 on account of the brilliant copper-red reflections afforded by 

 its cleavage surfaces. At a second occurrence found by Young 

 and Horton in the vicinity of the first, pieces about half an 

 inch in diameter were obtained. These latter crystals lacked 

 the copper-red luster characteristic of those from the first- 

 mentioned locality, and were in a more or less decomposed 

 condition. 



From a qualitative analysis Shepard concluded that war- 

 wickite was a fluo-titanate of iron and manganese with a small 

 percentage of yttrium. His results, however, were shown 

 later (cf. Smith, noted below) to be erroneous and need not be 

 discussed here. 



In 1846, Huntf published an article on a supposed new spe- 

 cies from Warwick, ~N. Y., which he called enceladite. The 

 material analyzed (I, below) was the impure altered warwickite 

 examined by Shepard, as Hunt himself recognized later. His 

 second analysis:}; (II, below) was made on a purer specimen but 

 showed a loss of nearly 20 per cent, which he attributed to 

 an accident. Hunt's analyses are as follows : 



I II 



Si0 2 18-50 



Ti0 2 28-20 31-50 



FeO 10-59 Fe 2 3 8-10 



MgO 22-20 43-50 



A1 2 3 ; 13-84 



CaO.._ 1-30 



H 2 7-35 Ignition 2-00 



101-98 



After the completion of Hunt's analyses several years 

 elapsed before further work was done on this mineral. About 

 1853, Brush and Smith, then engaged in the re-examination 



* This Journal (1), xxxiv, 313, 1838, xxxvi, 85, 1839. 



f This Journal (2), ii, 30, 1846. % Ibid., xi, 352, 1851. 



