Mineralogy and Geology. 273 
Il. MINERALOGY AND GEOLOGY. 
L Ponti tite, a new mineral ; by W. J. Taytor, (Abstract from “ Min- 
n Proceedings of Acad. Nat. Science, Philadelphia.)— 
_potash, containing two equi 
of anhydrous sulphates ea 
two er 
8 - 
: t that time supposed to be a new mineral from the differ- 
oa angle ner by Prof. Dana beeen it and other homeeom: 
and from a qualitative analysis that I made, from which 1t was 
considered a double sulphate of potash (the potash I then thought was 
e om and ammonia, and fal rao (in this judging erroneously from 
a The c composition is now definitely determined ae a thorough quantita~ 
Bs isborseny which, by the courtesy of . Genth, I have made 
narrow prisms 0 others short, not aaaiae Sore 
. as h 
ey — did not admit of measurement by a reflected ee that it 
se a candle. a 
Orystallination trimetric; form right chatntie gear 
‘ 
os T(cat from +2:0-2—= oe 12’ over 4. 
a faces - are small and indistinct except on one 
i=128° we have J: J =103° 12’, 0: sia 7 
Sabina the crystals are from 2 to 2°5; when free from the exte 
Ammonia, per cent, 
Potassa, s 
Soda, bad gies 
Sul h acl cent 44°9 
aa ae NS oes 
Organic residue, “ 2°30 
Inorganic andes: “ O11 
a trace. 
