422 Scientific Intelligence. 
in Macon County, N. C., a specimen of still another micaceous 
mineral having the same remarkable pyrognostic properties. It 
proved to be the best defined of any of this class of esis 
which I had examined, oo I shall designate it as Culsageei 
Besides vi above, there have been found several other aii 
minerals wh e pyrognostic and ag Sarg aphic characters indi- 
cate that they shenee to the same family, but which have not yet 
show that the effect is due to the same cause,—namely, to the es- 
caping of what we call water of spucalliensiea: I also expect to 
show that the several minerals referred to above are members of a 
family of hydrous silicates closely allied and aie to the well- 
known family of anhydrous silicates called the micas, and that 
their molecules differ from those of the ae vee micas chiefly i in 
miculites,’ using the original n “mica” is now anil 
to desig nate a class; and I shall eo the three species (or varle- 
ties ?) of, his sions Jefferisite, puenge eite and Hallite ; which 
Teper , of “West Chester.—The crystals of st fein cleave 
like mica, pan g thin but unelastic folia. The aie Pye 
are marked enanrilacly by lines, crossing at Oe of ‘ and 
120°. In some cases there is a ten. as in a a of “ne 
mb. 
optical axes, as in the Meee: number of mi cas, L. 
is parallel to one of these lines, as indicated in 22 
2 
double refraction is epee ly negative, but the 
angle between the ants axes varies in the it 
most remarkable ner. I have measure 
— intermediate condition ns. Owing to to the dad yellow color, aa 
plates b ecome Neat lo at a very es aaeted thickness, and for this 
reason it is im O measure t he angle with great precision. 
