Brush and Dana—Fairfield County Minerals. 41 
P.O; RO; RO H,O 
~thesed Reg. 3 2 8 15 
nara 1 & 4 3 9 18 
Eosphorite 1 1 2 4 and 
P,0O, : RO,+RO : H,0 
: . Rg. 1 - 34 : 
Childrenite | mr ME i 3 : 4} 
Eosphorite 1 3 : 4 
It can hardly be doubted from the above relations and the 
other facts given that the two species are in fact isomorphous, 
although the uncertainty that hangs over the composition of 
childrenite makes it useless to compare the formulas. It is 
quite possible that, when the composition of childrenite shall 
be definitely settled, it will be found to be analogous to that 
given for eosphorite. It cannot be questioned, however, that 
the two species though closely isomorphous, are at the same 
time perfectly distinct: the physical characters, the habit of 
crystals, and method of occurrence speak emphatically for this. 
Chemically, too, they are not to be confounded, although they 
may be similar compounds; eosphorite is essentially a phos- 
phate of aluminum and manganese, and childrenite of alumi- 
num and iron. 
Pyrognostics—In the closed tube eosphorite decrepitates, 
whitens, gives off abundance of neutral water, and the residue 
turns first black, then gray, and aa liver-brown with a 
i .B. in the forceps it 
P,0, 26°93 
A110; l “710 
FeO 5°86 
od Pale Sieve 19°21 
CaO 2°58 
H,O 12° 
Residue 14°4 
A lk a 4 aa 2, traces 
\ ss 100-61 
An examination of the residue insoluble in acids proved it 
to consist chiefly of quartz. The 0:144 gram of insoluble resi- 
due gave 0-131 silica (92°8 per cent), and contained besides traces 
of iron, alumina and perhaps other bases. The examination 
