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L. On the Position of Lierrite in the Mineral Series. By E. J. 

 Chapman, Professor of Mineralogy and Geology in University 

 College, Toronto, Canada West*. 



1\ FUCH uncertainty still prevails regarding the true compo- 

 JJTX sition of Licvrite or llvaite. The earlier analyses of this 

 mineral, those of Vauquelin and Collct-Descotils, made the sub- 

 stance essentially a silicate of sesquioxide of iron and lime. 

 Stromeyer's analysis, which followed those of the above-named 

 chemists, gave the iron, on the other hand, as protoxide. A 

 subsequent examination by Von Kobell disclosed the presence of 

 both oxides, as fully established by the later analyses of Ram- 

 melsberg and others. These analyses, the correctness of which 

 it is impossible to doubt, do not lead, however, to any general 

 formula ; nor can any formula of a satisfactory character, in a 

 mineralogical point of view, be obtained from them. It%ill be 

 as well to quote their results before proceeding with our inquiry. 

 A is Stromeyer's analysis, as calculated by Von Kobell ; B, that 

 of Rammelsberg ; C, WackernagePs ; and D, Francke's, — all of 

 Elba specimens. E is an analysis by E. Tobler, of a specimen 

 from Herbornseelbach in Nassau. (Ann. Chem. und Pharm. 

 vol. xcix. p. 122. Also Ramnielsberg's Mineral- Chemie, p. 740.) 



A. B. C. D. E. 



Silica 29-28 29-83 29-45 29-61 33-30 



Sesquioxide of iron 23-00 22*55 2578 21*09 22*57 



Protoxide of iron 31-90 32'40 28-60 3271 24-02 



Protoxide of manganese. . 1*43 1-50 0*94 1-55 6*78 



Lime 1373 12*44 15*49 14*47 11*68 



Alumina 0*61 



Water 1*27 1*60 .... .... JL\L2 



101*27 100*32 100-26 99'43 99*47 

 Eammelsberg deduces from the above the following oxygen- 

 ratios, and calculates from these the formula given below, truly 

 stating, however, at the outset, " es geht hieraus das wahre Ver- 

 haltniss nicht mit Sicherheit hervor." 





RO. 



R2 3 . 



SiO 2 . 













A.... 



.. 11-33 



6-90 



15*2] . 



.=4-9 



3 



66= 9-8 



6 



13*2 



15.... 



.. 11*08 



6-76 



15-49. 



.=4-9 



3 



6*9= 9*8 



6 



13*8 



C... 



,. 11*01 



774 



15-29. 



.=4-2 



3 



5-9= 8*4 



6 



11-8 



D.... 



.. 11*75 



6-33 



15-37. 



.=5-6 



3 



7*3=11*2 



6 



14*6 



E.... 



.. 10*19 



6-77 



17'29. 



.=4-5 



3 



7-7= 9*0 



6 



15*4 



I. 5(2 RO, Si0 2 ) + 2(Fe 2 3 , SiO 2 ). This requires the oxygen-ratio, 

 10:6:14. 

 II. 3RO, 2Fe 2 3 +6(RO, SiO 2 ). This assumes the sesquioxide to play 

 an electro-negative part, and requires the oxygen-ratio 9:6: 12.J 



III. 2(2 RO, Si0 2 )-f Fe 2 O 3 , SiO 2 . This formula requires the oxygen- 



ratio 4:3:6. 



IV. 9(2RO, Si0 2 ) + 2(2Fe 2 3 ,3Si0 2 ). This exacts the oxygen-ratio 



18:12:30. 



* Communicated by the Author. 



