A. J. Moses — Mineralogical Notes. 49 L 



sulphide as evidenced by effervescence and odor in the subse- 

 quent solution, and also made evident by the very low result 

 for S0 3 . The comparison therefore fails for S0 3 and ignition. 

 The other results were : 



CaO .... 24-174 



A1„0 3 8-298 



H„0 (110°) 30-613 



H 2 (ignit.) 15-514 



Si0 2 '. 3-497 



Recalculated as in No. 1 these correspond to 



CaO 25-04 



A1„0 3 7-18 



H„0 (115°) 32-68 



H 2 (red heat) 15-76 



Another determination yielded CaO 23445, Si0 2 3-920. Re- 

 calculating as before we find CaO 25-55. 

 The comparison therefore is 



Arizona mineral — 

 No. II. No. III. 



No. IV. 



Ettringite of 

 Ettringen. 



25-04 



25-55 



27-27 



7-18 





7-76 



19-03 





16-64 



32 68 

 15-76 





I 45-82 





Loss 



2-51 



No. I. 



CaO 26-31 



A1 2 3 9-72 



S0 3 18-54 



H„0(115°) 34-53 



H^O (red heat).. 10-88 



If the loss in Prof. Lehm aim's analysis is taken as S0 3 the 

 comparison is still more striking and my own results in No. II 

 proved the probability of such a loss. 



Analysis No. I of the Arizona mineral was very satisfactory 

 in all respects, needed very slight deductions and recalculations 

 and I prefer to regard the other determinations as confirmatory 

 but not worthy to be averaged with this of No. I. The 

 formula suggested for ettringite was 6CaO, A1 2 3 , 3S0 3 , 

 33H 2 ; but the analysis of No. I suggests a more simple 

 formula very closely fitting the analysis. 



CaO ........ 



Al 3 3 



so,.. 



H 2 (115°) 34-53 



H 2 (red heat) 



Am. Jour. Sci.— Third Series, Vol. XLV, No. 270. — June, 1893. 

 34 



No. I. 





Appr 



Dximate ratio. 



26-31-4- 56 



•470 





10 



9-72-T-102 



•095 





2 



18-54H- 80 



•232 





5 



34-53-h 18 



1-918 





40 



10-88-4- 18 



•605 





14 



