Pre 
and the Products of its Transmutation. 137 
Soda, . petioh Peep at 0°35 0:35 
temas, avy, ca a 408 4:23 4:23 
Carbonate of lime, . 7°80 7°80 7°80 
99°19 
The quantities of oxygen being— 
eters, 8 OS, 25:94 4 
Alumina, ; . 10°75 
Peroxide of iron, . 44 } Met Lhe 
Lime, .. : : 95° 
Magnesia, : ' 69 ; 
Ba URRER RS gait rs oreo 
Brau, boptlayfoue-a9 
Water, . 4 wt BIT6 0:58 
This scapolite differs, like the mica, from the other mi- 
nerals in the oxygen ratio of Si O, and RO. The quantity 
of the mono-atomic bases is, as in the mica, less than that 
corresponding to the formula (RO), 2.SiO, + 2(R, O, Si O,). 
Moreover, the quantity of the bases R, O, is less, that of water, 
greater than in the other minerals. - Apart from the physical 
characters, the advanced alteration of this mineral is indicated 
by the high percentage of silica, the small percentage of 
lime, and the large quantity of water it contains. There is 
indeed a remarkable similarity between its composition and 
that of the mica. | 
Comparing as before its percentage composition I. with 
that assumed to represent the original scapolite I1.— 
FE. . It. 
Silica, . j I 57°20 49°5 
Alumina, . ; 26°35 27°5 
Peroxide of iron, . 1-88 
Lime, . : ; 3°84 15:0 
Magnesia, . 1:98 
Potash, : , 8°34 
Soda, . L 0°41 8:0 
100-000 100-000 
it appears that while scapolite generally contains three or 
four times as much soda as potash, this altered mineral con- 
tains twenty times as much potash as soda; magnesia is pre- 
sent in nearly double the quantity that is found in unaltered. 
‘seapolite. It appears, likewise, that alumina has been re- 
