ie oJ 
Formation of Crystals in Geodes. 287 
they rivalled both in perfection of form, and in transpar- 
ency. Count Bournon caused numbers of these geodes to 
be broken ; some of them were full of water; ona partic- 
ular occasion a happy fracture left half of one of these 
geodes, containing unspi!t the liquor which it had enclosed. 
Roeciving that the fluid moved heavily, in a kind of mass, 
{almost like mercury,) he concluded that it must be a very 
concentrated solution, and as it was in the middle of a very 
warm day in the month of July, the fluid was all evapo- 
rated, in little more than a quarter of an hour, and there 
remained in the geode, a spongy amorphous crystalline 
mass of carbonate of lime. This fact is certainly very 
rere as to the formation of crystals in geodes. Count 
urnon observed ‘the same thing at Voaey, about the 
te period, but the geodes were composed of black oat 
of manganese lined with crystals of carbonate of lime. — 
Ifthe above facts should appear to others as they do to 
us, worthy of being preserved, we hope that all similar 
facts which our readers may be acquainted with, will be 
communicated to the public. They may throw important 
light upon cera = ah natural processes. 
¥i3i Sines ‘thie fabote was written the orem 
ph has been observed in the 15th number of the 
burgh Philosophical Journal. 
“On the Formation of Rock-Crystal, 
- Spallanzani remarks that the numerous beautiful rock- 
ery: 
it Sey: cavities of the Carrara marble, continue 
» form, and from a pure acid fluid. Ripetti i in his 
tract « Sock Alpe Apuana ei Marmi di Carrara, 1811,” 
adduces some new observations in favour of this opinion, 
and telis us, that on opening a drusy cavity, there was 
found 14 Ib. "of the above fluid, and among the solid ie 
tals, a oft mass the size of the fist, which, ya posure 
r, hardened into a substance having t acter of 
According te Daubuisson and Beaudant, the 
izary is sometimes Ue in a soft state.” 
