304 Alger's Localities of Rare Minerals, 
hardness, color, specific gravity and pyrognostic characters, 
can be accounted for by the well established fact of the iso- 
morphous replacement among the constituents of certain min- 
erals 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 peroxide 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 re- 
placed so much of the oxide of zinc, we make up, very nearly, 
the essential constituents as shown in the analyses of Auto- 
malite 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 zine + 11 per cent. protoxide of iron + 7 per cent. 
protoxide of manganese — 35 per cent. oxide of zine; which 
is nearly the exact quantity found by Abich in the crystals 
from Franklin. We may then state the constituents as follow : 
Oxygen. Ratio. 
Alumina 30.49 14.24 3 
Peroxide of iron, 3000 . 919 j 22-3 
Protoxide of iron, 11.93 2.12 
Protoxide of manganese, 7.60 m TH 5 
Oxide of zinc, 16.80 3.34 
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, 
us: 
Oxygen. Ratıo. 
Alumina, 57.09 26.66 3 
Oxide of zinc, 34.80 6.92 } 
i 22 "i 872 1 
Protoxide of iron, 4.55 1.04 
