192 . Scheerer on Isomorphism. 
be replaced by water, and the formula in consequence becomes 
(Cu)* P+ 5a, agreeing with the Bodenmais vivianite and miul- 
licite. 
3. Phosphate of Copper, from Ehl, near Rheinbreitenbach. 
This consists, atcording to Bergmann, of phosphoric acid 
24:93, oxyd of copper 65:99, water 9:06 = 99-98, corresponding 
to the oxygen ratio 13-99P : 1331 Cu: 8058 ; whence we de- 
cup the So 3Cus P+ 10, requiring an oxygen ratio of 
4. Phosphate of Copper, ftom Hirschberg. 
According to Kiihn, its constituents are, phosphoric acid 20°87, 
oxyd of copper 71°73, water 7-40 = 100-00; whence we obtain 
the oxygen ratio, 
11-69 P : 17-66(R) Tae 
1169 : 17-54 ‘ (Cn)! Be. 
IV. Arsentares. 
_ As the relative quantities of the peroxyd and the protoxyd of 
iron have not yet been ascertained with accuracy in scorodite and 
in pharmacolite, no calculations can be here entered upon wit 
respect to the formula these minerals would receive, by consider- 
ing their water as a basic constituent. 
A. Arseniates of Earths. 
Picropharmacolite. 
The analysis of Stromeyer gives arsenic acid 46-971, lime 
24646, magnesia 3:223, oxyd of cobalt 0-998, water 23-977 = 
99°815, corresponding to— 
| 1630 As : 15-47 (R) 6 i 
1600 31600 $ se sa 
the formula of vivianite, libethenite, and earthy blue iron, Since 
pharmacolite contains no earth but lime, it is not to be assumed 
. 
that any replacement by water is brought into play in that mineral. 
B. Arseniates of Cobalt. 
Cobalt Bloom. 
According to Berzelius, its formula is Co? As+6H, which, as 
protoxyd of iron and protoxyd of cobalt are isomorphous, and as 
wo make 3H = 1Co, may be expressed likewise thus, 
(Co)* As, by which it is rendered analogous to the Cornish vivir 
anite ; and the agreement that has been proved by Gustavus Rose 
