160 
CONTRIBUTIONS TO CHEMISTRY AND MINERALOGY. 
[BULL. 167. 
Formula. 
Per cent of 
combined 
alkalies by 
analysis. 
Equivalent 
of Na^O in 
solution. 
Anal cite 
NaAl(Si0 3 ) 2 .H,0. 
r AlNaSi 3 8 
14.00 
1 9. 18 
12.10 
j. 11.09 
21.39 
1.00 
7.10 
.10 
.09 
.07 
.07 
.06 
.05 
.05 
Oligoclase, Bakersville, N. C . 
Albite 
lAl 2 CaSi 2 8 
AlNaSi 3 0« 
Wernerite, St. Lawrence 
County, N. Y. 
Leucite, Vesuvius, Italy 
Stilbite, Nova Scotia 
Chabazite, Nova Scotia 
rCaiAleSieOsB 
lNa4Al 3 Si 4 2 4Cl 
KAl(Si0 3 ) 3 
Al,(Si 3 8 ).,(CaNa,).6H,0 
Al 2 Si04Si; 5 8 (CaNa 2 ).6H 2 . . . 
It is worth noting in comparing the depth of color produced by phe- 
nolphthalein solution, as shown in Professor Clarke's paper, with the 
percentage of alkali in solution as shown in this work, that some of the 
minerals which give a deep coloration with the former, show in the 
above table a comparatively small amount of alkali in solution, and 
vice versa. Muscovite, for example, while giving only a faint colora- 
tion with phenolphthalein, contains in solution alkaline compounds 
equivalent to 0.49 per cent K 2 0; pectolite, with 0.57 per cent Na 2 ? 
being the only one of the series showing a larger amount. The cause 
of these discrepancies remains to be ascertained. 
