1818.] Dr. Choke on Petalite, and a Neiv Mineral. 365 



Article XI. 



Further Account of Petalite, together with the Analysis of another 

 neiv Swedish Mineral found at Gryphytta, in the Province of 

 Westmania, in Sweden, &jc. In a Letter to the Editors. By 

 Edward Daniel Clarke, LL. D. Professor of Mineralogy in 

 the University of Cambridge, Member of the Royal Academy 

 of Sciences at Berlin, &c. 



GENTLEMEN, 



Since I communicated to you the result of my analysis of 

 Petalite, I have received intelligence from Mr. Swedenstierna of 

 Stockholm, to whom I had written upon the subject of this 

 mineral, that the loss which I have stated in the sum of its con- 

 stituents refers to the presence of a new chemical substance, 

 namely, a new alkali, which Mr. Arvedsou, the pupil of Mr. Ber- 

 zelius, has discovered in Petalite in the proportion of three per 

 cent. According to the Swedish chemist, Petalite consists of 

 80- parts of silica, 17- of alumina, and 3* of this new alkali, to 

 which Mr. Berzeliush&s given the name of lit hi on. But there is 

 a constituent in Petalite which has escaped the notice of the 

 discoverer oi'lithion; namely, manganese ; and as this metal has 

 been obtained from it in the proportion of 2-i- percent, according 

 to my own analysis and also that of Mr. Holme, and, moreover, 

 as the Swedish chemist has confirmed my account of the silica 

 and alumina, I think there can be no doubt, if we have both 

 analyzed the same substance, that the constituents of Petalite 

 will be found as follow : 



Silica 80-00 



Alumina 15-00 



Manganese 2-50 



Lithion 1-75 



Water 0-75 



100-00 



As my authority for this statement, I am ready, at any time, 

 to produce the mineral which 1 have analyzed ; trusting in the 

 accounts which I have received for the presence of the new 

 a/kali, and that the trials, in both countries, were made upon the 

 same substance. There is now more reason than ever for calling 

 this mineral Berzelite ; because it is evident that the old name 

 of Petalite was not applied to the mineral containing lithion. Of 

 the importance of Mr. Arvedson's discovery, all your chemical 

 readers must be aware : it will be followed by a complete revolu- 

 tion in the analytical part of mineralogy : many are' the sub- 

 stances which it will be necessary to examine again ; and the 

 presence of this new alkali will, perhaps, be ascertained in other 



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