Rahtite, Marcylite and Moronolite. 211 
atacamite. The following is Mr. Tyler’s account of his investi- 
gations, 
that which was oxydized to sulpHuric acid was precipitated 
from the solution with chlorid of barium and weighed as sul- 
phate of baryta. ae 
10137 grm. of the mineral gave 8182 Cu?S, containing *6444 
Cu; 027 Fe203, containing ‘0189 Fe; 009 CaO, 
‘8110 grm. gave -6437 Cu?S, containing 5140 Cu; and 0205 
4 
No. 1 No. 2 os hs. 3. Average. ang bcm rene 
Cu So57° et. 63-4 
Fe 1°86 gay: 1-82 1:82 
CaO 0°88 ae. Se 0-88 0°88 
Na trace shake trace sees 
8 ae 17-22 17-22 17°54 
Cl trace sees ees ce bees 
O 8:00 800 
supposed) 7s 9-00 9-00 
100°39 
. The composition then would be this: 
~CuS 4770 =< 31°7Cu and 1608S 
FeS 2°86 1-82 Fe “ tee 
CuO 39°70 31-7 Cu , 
aOSO2 2°18 0°88 CaO - 1:25 80 or 05S 
HO 9:00 eeee eee 
10139” 
