Intelligence and Miscellaneous Articles. 56 1 



may not have been derived from the gangue of slate, from which it 

 is difficult to obtain the mineral entirely free. Its infusibility before 

 the blowpipe would seem to show this. It has been suggested, also, 

 that a part of the iron may have been in the state of protoxide. It 

 seems impossible, without some such supposition, that substances 

 so closely resembling each other in all their physical characters, 

 should differ so much in chemical composition. Now, if the potash 

 be left out, and the peroxide of iron be changed into protoxide, the 

 ratio between the atoms of acid and bases is nearly the same as in 

 ottrelite, if we unite the atoms of magnesia and iron as isomorphous 

 with each other. Ottrelite, also, is not easily separated from its ma- 

 trix, but the larger size of its plates would seem to render it more 

 easy to obtain pure specimens for analysis ; and it is to be observed 

 that Damour repeated his analysis, and obtained precisely the same 

 result. It is remarkable that Rammelsberg has alphabetically in- 

 serted phyllite, but has given no formula for its constitution. It 

 seems proper that the name of phyllite, on the ground of its priority, 

 and because it expresses so well the ordinary appearance of the mi- 

 neral, should stand, and that of ottrelite be abandoned*. 



Dysluite identical with Automalite. 



I am satisfied, from recent observations, that these two minerals, 

 as they occur in New Jersey, should form but one species. The dif- 

 ference in hardness, colour, specific gravity and pyrognostic charac- 

 ters, can be accounted for by the well-established fact of the isomor- 

 phous replacement among the constituents of certain minerals which 

 do not differ in crystalline form. In dysluite we have but thirty 

 per cent, of alumina, the acting acid principle in the mineral, while 

 in automalite we have sixty per cent. But the peroxide of iron, 

 which is isomorphous with the alumina, amounts to nearly forty-two 

 per cent.- Now, if we suppose about thirty per cent, of this per- 

 oxide of iron to have replaced the same number of atoms of alumina 

 in automalite, and the eight per cent, of protoxide of manganese to 

 have replaced so much of the oxide of zinc, we make up very nearly 

 the essential constituents as shown in the analyses of automalite by 

 Ekeberg and Abich. It is to be observed that the latter chemist puts 

 down the iron as protoxide in the Franklin automalite. If it should 

 prove that the iron exists in dysluite in both states of oxidation, the 

 twelve per cent, remaining out of the forty-two may be protoxide, 

 replacing so much oxide of zinc. So that in this view of the case, 

 the 17 per cent, oxide of zinc -f 11 per cent, protoxide of iron -j- 7 

 per cent, protoxide of manganese=35 per cent, oxide of zinc, which 

 is nearly the exact quantity found by Abich in the crystals from 

 Franklin. We may then state the constituents as follow : — 



* BrooKe has supposed phyllite to be identical with gigantolite. If we 

 compare the analysis of gigantolite with Damour's analysis above, the evi- 

 dence of their identity (supposing ottrelite to be a purer variety of phyllite) 

 is much more marked, and the ratio between the atoms of acid and bases 

 is nearly the same in each. 



