and the allied minerals. 



Ill 



1. 2. 3. 



Si0 2 -847 -861 -869 



Fe 2 3 -116 -122 -115) 



A1 2 3 -010 j" iZb 



FeO -239 ) -237 ) „ nq -260 \ 



MgO -057 f 296 -066J- 3 ° 3 -044 \ 304 



Na 2 -113 -115 '099 



H 2 0. -310 -228 '088 



showing as close an agreement among themselves and with the 

 figures before given as could be expected between analyses 

 made by different persons, using different methods, and on spe- 

 cimens from different localities. The ferric oxide is high ac- 

 cording to these figures, and still higher in 3, if we use those 

 originally given by Dolter for his analysis; but this is easily 

 explained if one examines a specimen of the " Cape" crocidolite, 

 the fibers of which are seen to be more or less coated with 

 ferric hydrate, so that it would be difficult, if not impossible, 

 to select an absolutely pure sample for analysis. The mineral 

 from Hhode Island seems to be of purer material, and hence 

 better fitted for an examination on the results of which a 

 formula is to be calculated. 



2. Abriachaniie. 



Heddle* has given the following analysis for a mineral which 

 he named Abriachanite ; the 2d column showing the calculated 

 ratios : 



•099 

 •430 



•096 

 •140 



Total. 99-71 



Here we have the ratio Si0 2 : Fe 2 O s : FeO : MgO : Na 2 : 

 H 2 0=9 : 1 : 4 : 1 : 2, where MgO ; FeO=2 ; 1. If now we 

 correct the analysis of crocidolite from the Yosges Mountains 

 given by Delessef so as to make the proportions of ferrous and 

 ferric oxide agree with these ratios, we obtain results as above. 



Ahriachanite. 





Vosges Crocidol 



1. 2. 





1. 



Si0 2 51-15 



•853 



Si0 2 53-02 



Fe 2 3 :. 14-92 



•090 



Fe 2 3 .. 15-95 



FeO 9-80 -136 ) 





FeO 11-29 -157 



MgO... 10-80 -270 \ 



•426 



MgO... 10-14 -254 



CaO ... 1-12 -020 ) 





CaO ... 1-10 -019 



Na 2 .. 6-52 -105 [ 

 K 2 0-63 -007 j 



•112 



Na 2 .. 5-69 -092 



K 2 0-39 -004 



H 2 3-82 



•212 



H 2 0_... 2-52 



Moisture -95 







* Min. Mag., iii, 61, 1879. 



t Ann. des Mines, III, x, 317, 1836. 



