Se ee a a ee a ey ee 
Sear e she tae gaa te ca paper yan - 
. is wrong and bad, the Greek signifying 
as 
J. D. Dana on the Feldspar group of minerals. 405 
sili ing doubled, i 
this other difference that the protoxyd bases are eaclusivel, 
alkaline ; no iron is present fi te as protoxyd or pacer | 
This increase of the silica by a simple ratio is evidently par- 
origin, and as the Spodumene is often imbedded in free 
quartz, showing that there was no lack of silica at its forma- 
tion, it would appear that the small difference of constitution 
as to the bases, above pointed out, determines the proportion 
of silica, It is quite possible that iron may have the same in- 
fluence as the non-alkaline metals even if it replace alumina.* 
From the above examples it seems to follow, first, that under 
the bases are all protoxyds; and as resp bit and ca 
may well be related species. Now Chry ite i 
Tatio, for bases and silica bei : i ‘ 
phane has a large excess of silica, the pags pee Fe bein: 
Again, Meliphane (melinophane) appears to bear the same relation in form and 
ie : ite, : re hm to Chrysolite. [The name melinophane 
ing either ash- or millet-like, instead of honey- 
author intended. It should be melifophane or meliphane.] 
