562 Intelligence and Miscellaneous Articles. 



various times in the author's laboratory. It was analysed first by 

 M. Wornum and afterwards by M. Peretz. Subsequently, through 

 the liberality of M. von Samarski, the author was enabled to have 

 the analysis repeated by Mr. Chandler, according to improved 

 methods. 



Hitherto Samarskite has been found only in the Ilmen Mountains, 

 near Miask, in the Ural. It is indisputably in its original condition, 

 and has not, like so many columbites, undergone decomposition 

 under the influence of the atmosphere and of time. It has there- 

 fore always been found of the same specific gravity, namely, 

 between 5*6 and 5*7. Ignition causes no important change in its 

 external appearance, but, nevertheless, alters its density in a very 

 remarkable manner. During ignition it becomes phosphorescent, 

 and its specific gravity is afterwards found to have fallen as low as 

 5*37 or 5*4 ; whereas all other minerals which become phosphores- 

 cent on ignition are found to have afterwards a greater specific 

 gravity than before. 



Samarskite occurs compact and also crystallized, the crystals 

 having exactly the same form as columbite, but being easily distin- 

 guished from crystals of the latter mineral by their different fracture. 

 The two minerals are evidently isomorphous, and grow into one 

 another, as has been already remarked by Hermann (who, however, 

 gives to Samarskite the name Yttroilmenite) . 



Although Samarskite contains hyponiobic acid, this is not the only 

 electro-negative substance which forms an essential constituent of it. 

 In addition to very small quantities of tungstic and stannic acids, it 

 contains a considerable quantity of uranic oxide, amounting, indeed, 

 to as much as 20 per cent. The bases contained in it are chiefly 

 protoxide of iron, a little protoxide of manganese, and a not quite 

 inconsiderable quantity of yttria. The oxygen of the bases, counting 

 that of the yttria, is one-third of that of the hyponiobic acid and 

 uranic oxide taken together. Hence, hyponiobic acid and uranic oxide 

 being similar in atomic composition, Samarskite has the same atomic 

 composition as columbite. 



Fergusordte. — This is a rare Greenland mineral, described a long 

 time ago by Haidinger, and since examined by Hartwall. More 

 recently, M. Weber has analysed it afresh ; and the results of his 

 investigation agree in essential points with those of Hartwall, 

 except that he has recognized the metallic acid contained in it as being 

 hyponiobic acid. 



Fergusonite appears, like the generality of minerals from Green- 

 land, to occur in its original undecomposed state, notwithstanding 

 that Haidinger states its specific gravity to be 5 -83 8, while Weber 

 found 5-612. 



Fergusonite contains, besides hyponiobic acid and a small quantity 

 of oxide of uranium, zirconic acid, not, however, to any notable 

 amount, and a smaller quantity of stannic acid. The bases are chiefly 

 yttria, a small quantity of protoxide of cerium, and a still smaller quan- 

 tity of protoxide of iron. 



Seeing that the atomic constitution of zirconic acid differs from 

 that of hyponiobic acid, we cannot assume that the bases are com- 



