122 Scientific Intelligence. 
ck which contains them. ‘These veins, however, are injected inti- 
into the interior of crystals of specular iron and of quartz, proves that 
these three minerals have been precipitated, if not simultaneously, at 
least under the same conditions. Now the specular iron of these veins 
recalls by its brilliancy and peculiar form the specular iron of volcanic 
regions, which as has been shown by Gay Lussac and Mitscherlich, 
has been produced from the decomposition of chlorid of iron by the 
vapor of water. 
We seem authorized in assigning a similar origin to the specular iron 
ous condition by methods heretofore known, disposes itself in crystals 
when its chlorid is treated at an elevated temperature by the vapor of 
water; so it is the same with silicic acid. us by a threefold réason 
with the three species of titanic acid—the fl 
frequent, the fluo-silicates (mica rich in fluor 
il Te 
