562 Intelligence and Miscellaneous Articles. 



j 23-43 3 



Oxygen. Ratio. 



Alumina 30-49 14-24 \ 



Peroxide of iron 30-00 9' 19 



Protoxide of iron 1 1-93 2-72 ' 



Protoxide of manganese .. 7*60 T70 V 7-76 1 



Oxide of zinc 16-80 3-34 J 



Here it is evident that the atoms of acid and bases are to each other 

 as three to one, which is the case also with automalite, taking 

 Abich's analysis, and grouping the isomorphous bases, thus : 



Oxygen. Ratio. 



Alumina 57*09 26'66 3 



Oxide of zinc 34-80 6-92] 



Magnesia 2'22 -76 > 8'72 1 



Protoxide of iron .. 4'55 1-04J 



Dr. Thomson, the only chemist who has analysed dysluite, reckons 

 all the iron as peroxide, and as the principal basic constituent of the 

 mineral, which, in his view, consists of the aluminates of iron, zinc 

 and manganese. Rammelsberg, in stating the analysis, has given 

 both oxides, and the atoms of alumina and peroxide of iron, as put 

 down by him, are 22- 80, and those of the isomorphous bases — pro- 

 toxide of iron, protoxide of manganese and oxide of zinc — are 7*83 

 (7'89 ?) ; thus giving the same ratio as that above stated. 



But other reasons may be urged why dysluite should be regarded 

 only as a variety of automalite. I have seen specimens on which 

 there were crystals well claiming the name of dysluite, as well as 

 others equally entitled to the name of automalite ; while there were 

 yet others evidently passing from one into the other, — the bright and 

 perfect crystals of automalite gradually losing their lustre, becoming 

 porous, comparatively brittle and soft. I think if these circumstances 

 had been attended to in the early history of the mineral, the name 

 dysluite would long since have departed from the catalogue of 

 mineral species. 



Polyadelphite. 



As Dana, in the new edition of his Mineralogy, has very properly 

 included this mineral under the species garnet, I merely refer to it, 

 to give further evidence of the correctness of his opinion from cir- 

 cumstances connected with its occurrence at the locality. It is evi- 

 dently a granular, imperfectly crystallized yellow garnet, and the 

 specimen which I received ten years ago from Prof. Nuttall, con- 

 tains mechanical mixtures which it would be impossible to separate 

 from it, so as to give us entire confidence in its analysis. To these, 

 I believe, we may attribute its departure in composition from the 

 common brown or yellow garnet, though it does not differ much from 

 the brown garnet of Franklin, analysed both by Dr. Thomson and 

 Mr. Seybert. 



Beaumontite of Levy, and Lincolnite of Hitchcock. 



In a paper read before the Boston Society of Natural History, and 

 since published in their Transactions, and in the American Journal 



