276 Description of FERGUSONITE, 



ern extremity of East Greenland, and, besides Zircon, it is asso- 

 ciated with Mica and Albite, and imbedded in Quartz. The lo- 

 cality of Fergusonite is Kikertaursak, near Cape Farewell, where 

 it is found in imbedded groups and single crystals, in white 

 quartz. The specimens of this species were brought from 

 Greenland by Sir CHARLES himself, and were presented by him, 

 on his arrival in this country, to Mr ALLAN. 



Fergusonite, under the name of Allanite, has been examined 

 by Mr CHILDREN before the blowpipe *. The results of his ex- 

 periments agree pretty well with those given by BERZELIUS of 

 the Black Yttro-tantalite from Ytterby. Its slow but perfect 

 solubility in salt of phosphorus, leaving a long time some par- 

 ticles undissolved, the property of this glass-globule to become 

 opake by flaming, when saturated to a certain degree, and, on 

 cooling, when still farther saturated, may indicate the presence 

 of tantalum and yttria ; and even the rose colour, which it as- 

 sumes under certain circumstances, accords with the re-action of 

 a small quantity of wolfram, as quoted by BEIIZELIUS. It will 

 depend upon future examination of its physical properties, whe- 

 ther the black Yttro-tantalite can be arranged among the varie- 

 ties of Fergusonite. They agree in some respects, but their 

 differences in others are such, as, if ascertained with sufficient 

 exactness, would alone prove the two substances to be dif- 

 ferent species ; while the circumstance, that we know nothing of 

 the regular forms of the black Yttro-tantalite, renders every con- 

 jecture doubtful. 



It is the more necessary to leave the decision of this point to 

 future observations, as there are some crystallised specimens in 

 Mr ALLAN'S collection, evidently belonging to a different species 



* BERZELIUS on the Blowpipe, translated by J. G. CHILDREN, p. 291. 



