24 VBOCEEDINQS OF SOCIETIES. 



The Rev. S. Haughton, F.T.C.D., Professor of Geology, read the follo\ving — 



ON THE ANALYSIS OF SPODUMENE AND KILLINITE. 



Having been asked to arrange the minerals belontring to this Society, and finding 

 among them fine specimens of Spodumene and KiJlinite, both of which mineraU 

 are becoming now rare, 1 was led to make a particular examination and analysis 

 of them, especially as the published analyses of Spodumene are, for the most part, 

 confessedly imperfect, having been made at a time when perfect atomic analysis 

 was not carried to as great perfection as it is now. 



Spodumene is a rare mineral, which has hitherto, as geologists are aware, been 

 found in Europe, only in Sweden, in the Tyrol, and in Ireland ; not being found 

 in any other part of the British Isles. A careful analysis of the Society's specimens 

 gave the following result : — 



ANALYSIS OF SPODUMENE. 



= I 



He next examined the Killinite, with a view to establish some doubtful points in 

 its history, and mentioned, that some time previous he had been given some 

 fine specimens of Killinite, from Killiney, of a leek green colour. These were handed 

 over to the llev. Mr. Galbraith, who had been engaged in an examination of the 

 ordinary hair brown variety of Killinite, and on analysis the two varieties proved 

 to be identical, except in colour. 



It has been supposed that the two species, Killinite and Spodumene, ought 

 really to be considered as one. To this theory the above analysis seems to oppose 

 a very great diflSculty ; for, adopting Berzelius's theory of oxygen atoms, we will 

 find that in Spodumene, as shown above, the oxygen in the acid is as two to one 

 of the oxygen in the base, while in Killinite it is as three to two. The lithia, 

 according to Galbraith, is altogether absent from the Killinite; and, according to 

 Mallet, who has also published careful analyses of this mineral, it exists as a 

 mere trace. 



The specimens of both these minerals, however, being very fine and perfectly 

 crystallised, Mr. Haughton was enabled to measure the angles, and thereby prove a 

 roost important fact, which is, that the angles of the crystals of the one mineral are 

 supplemental to those of the crystals of the other. This fact proves the perfect 

 identity of the two. To explain the seeming contradiction of the analysis, 

 we must take other matters into account. In addition to the difference 

 stated above, we find that Spodumene is anhydrous, and Killinite con- 

 tains 8 per cent, of water. We also find that whilst external appearances 

 are the same, the Killinite has a soapy feel, which Spodumene wants. This soapy 

 feel, which is generally looked on as a proof that we are dealing with an altered 

 mineral, gives us the clue to the whole matter. Killinite is an altered Spodumene, 

 which has become hydrated. The silica in it has followed the general rule and 

 become diminished by a fourth, and the lithia (one of the most soluble of the 

 ^kalis) has been dissolved out. 



Bev, J. Galbraith stated, that having this subject called to his mind by the 



