150 G. P. Merrill — Comjposition and structure of the 



" In calculating the analysis of the soluble portion to 100 

 per cent the S and an amount of iron (-56 per cent FeO) 

 sufficient to form FeS are first deducted." 



The present writer's attention was called to the stone bj 

 Mr. E. L. Preston of the Ward INatural History Establish- 

 ment, who kindly offered to furnish material for the petro- 

 graphic work. As will be noted by reference to the table, the 

 chemical composition is somewhat peculiar, in that the per- 

 centage amount of soluble matter is so large (37*63 per cent), 

 and yet, the amount of olivine, as indicated by the percentage 

 of magnesia (1*34 per cent) is small. It was this feature of 

 the analysis which first attracted Mr. Preston's attention. In 

 the paper above referred to this peculiarity is recognized, but 

 not satisfactorily explained. The statement is made that '' in 

 many stony meteorites olivine is a considerable constituent, 

 generally forming the bulk of the soluble silicate ; but in this 

 case the analysis shows olivine to be present in but small pro- 

 portions, if at all. It is interesting to see that both the solu- 

 ble and insoluble portions have practically the same molecular 

 ratios, the soluble portion reducing itself essentially to P K\^ 

 SiOg, in which P=Ca, Fe ; and the insoluble part to the same 

 formula, where P=Mg, Fe ; both being equivalent to alumi- 

 nous enstatite or pyroxene." 



''At the time this analysis was made it was impracticable to 

 supplement the work with the proper microscopical examina- 

 tion of sections, which doubtless, in conjunction with the 

 chemical evidence, would have satisfactorily determined the 

 minerals present. Without this microscopical knowledge, how- 

 ever, little that is definite can be said, except that there seem 

 to be present two simular molecules, the one in which lime 

 predominates being soluble, and the other, magnesian, being 

 insoluble, in hydrochloric acid. The other alternative is to 

 assume a complex molecule which is split into two sections by 

 the action of the acid." That neither of these conclusions is 

 even approxinately correct appears in the results given below : 



Three specific gravity determinations, made on fragments 

 from 15 to 25 grms. in weight, including both iron and stony 

 portions, yielded the present writer an average of 4*32. 



In thin sections the structure of the stony portions is found 

 to be holocrystalline granular, sometimes strongly cataclastic. 

 This latter structure is particularly conspicuous in those por- 

 tions rich in metallic iron, where the feldspars are often enclosed 

 in the form of sharply angular fragments in the iron or in its 

 numerous embayments, as shown in fig. 1. In the figure as 

 drawn the heavily shaded portion is metallic iron, the colorless 

 area anorthite and that finely dotted and granular silicates too- 

 badly stained to be drawn in outline. The appearance is not, 



