488 Chronicles of Science. [ July; 
The writer of this notice has in his possession a piece of timber, 
believed to be oak, which was found in Pontpean mine, Normandy, 
where it had no doubt lain from the period when the Romans worked 
the mine. It is intensely black, but as solid as it ever was. 
At the “Stream Works” for tin at Carnon and at Pentnam, in Corn- 
wall, seventy feet below the present surface, oak shovels have been 
discovered which were probably used by the British miners who sup- 
plied the Tyrian merchants with tin. Similar implements have been 
found in the ancient mines of Dartmoor, and in the Roman mines of 
Cardiganshire. ‘These instances sufficiently prove the preservative 
powers of the sulphates of the metals. 
MINERALOGY. 
An interesting examination of some minerals of the chlorite group 
has been made by Mr. John B. Pearse.* The diversities of colour 
among the varieties of the mineral species are in many cases still un- 
explained. The Kaémmererite from Lancaster county, Penn., for ex- 
ample, is of three kinds, one coloured pure green, a second red and 
green, while the third is pure red. Mr. Pearse’s investigations were 
to determine the cause of this variation. We cannot transfer to our 
pages all the results obtained and the discussion on them ; these must 
be sought in the original paper. The chief conclusion is, that “ the 
cause of the difference of colour is unanswered by analysis. It is 
possibly due to molecular arrangement.” 
The name of Grastite is proposed for the new green variety, and 
Grastite and Kimmererite may be supposed to be formed thus :— 
Grastite—1 atom of kaolin. Kammererite—1 atom of kaolin. 
2. a. olivine. 3 » olivine. 
5 »  brucite. 1 » Serpentine. 
5 »  brucite. 
Mr. T. Sterry Hunt commences in ‘ Silliman’s Journal’ his “ Con- 
tributions to Lithology.’t No one has contributed more to the 
Chemistry of Rock-formations than Mr. Sterry Hunt; we may there- 
fore regard those papers as valuable aids to our knowledge. Re- 
ferring especially to the formation of granite, and to Mr. Sorby’s dis- 
covery of fluid cavities in the quartz crystals,—one of the constituents 
of that rock,—Mr. Sterry Hunt has the following remarks, which from 
their high interest we think especially deserving of note :— 
“The admirable investigations of Sorby on the microscopic structure 
of crystals, have demonstrated that water has intervened in the crystalliza- 
tion of almost all Plutonic rocks. He has shown that quartz, both of granite 
and of crystalline schists, contains great numbers of small cavities partially 
filled with water, or with concentrated aqueous solutions of chlorides, 
sulphates of potassium, sodium, calcium, magnesium, sometimes with free 
chlorhydric acid. . . . As these fluid-cavities enclosed the liquid at 
an elevated temperature, its subsequent cooling has produced a partial 
* «The American Journal of Science and Arts.’ (Silliman.) Vol. xxxvii. No. 
110, March, 1864. 
+ ‘The American Journal of Science and Arts.’ (Silliman,) Vol. xxxvii. No. 
110, March, 1864. ~ 
