Intelligence and Miscellaneous Articles. 563 



bined in the same ratio with both acids. With the hyponiobic acid, 

 the bases are not combined to a neutral salt, as in the columbites 

 and in Samarskite, but they form a basic salt wherein the oxygen of 

 the bases amounts to two-thirds of that of the acid. With the 

 zirconic acid, on the other hand, the bases are combined in such 

 proportion that the oxygen contained in them is equal to that con- 

 tained in the acid, thus again forming a basic salt. 



It was announced some time ago by A. E. Nordenskjold that a 

 mineral similar to the Fergusonite of Greenland occurred, together 

 with yttrotantalites (which contain tantalic acid and not hyponiobic 

 acid), at Ytterby in Sweden. This Fergusonite contains, according 

 to Nordenskjold, no zirconic acid ; and its specific gravity, namely 

 4*89, is also considerably lower than that of the Greenland mineral. 

 The Fergusonite of Ytterby is the only mineral hitherto found in 

 Sweden which contains niobium. 



Tyrite.— This mineral has been supposed to be identical with 

 Fergusonite; but a carefully conducted analysis by Potyka has proved 

 that it consists of hyponiobic acid in combination essentially with 

 yttria and potash. Besides hyponiobic acid, the only acids contained 

 in it are very small quantities of zirconic, tungstic, and stannic 

 acids ; but, in addition to the bases already mentioned, it contains 

 protoxide of uranium, protoxide of cerium, and lime in somewhat con- 

 siderable quantities, together with very small quantities of the oxides 

 of lead, copper, and iron (but not of manganese), and an equally small 

 quantity of magnesia. The oxygen of the bases taken together is to 

 that of, the acids as 1 : 1|; and this ratio remains essentially the same if 

 the mineral is supposed to contain, in place of protoxide, sesquioxide 

 of uranium, this compound being regarded as an acid capable of 

 replacing hyponiobic acid — an assumption which the composition of 

 Samarskite justifies. But if the mineral may be regarded as a basic 

 salt, it is not a simple, but a double salt ; for potash and yttria 

 cannot mutually replace each other in combination. Tyrite consists 

 therefore essentially of basic hyponiobate of yttria and basic hypo- 

 niobate of potash. 



Tyrite contains, further, a somewhat considerable quantity of water, 

 which, as obtained by distillation, contains a little sulphuretted 

 hydrogen, and is milky from the presence of sulphur suspended in it. 

 This no doubt arises from a trace of enclosed iron-pyrites. Still, 

 notwithstanding the water contained in it, the mineral appears to 

 be essentially undecomposed. 



In the niobiferous minerals which have been examined, the hypo- 

 niobic acid is combined with strong bases in various proportions. 

 The quantity of oxygen contained in the hyponiobic acid and in the 

 oxides of similar composition, such as uranic oxide, is to that of the 

 bases — 



As 3 : 1 in the columbites. 



As 3 : 1 in Samarskite. 



As 3 : 2 in Fergusonite. 



As 3 : 3 in tyrite. 

 ■ — Monatshcricht d. K*Preuss. AkacL d. Wissenschqficn zu Berlin, 

 1862, p. 166 (March 13). 



2P2 



