202 On the Vents of Hot Vapor in Tuscany. 
_ 
. 
Lardarello and the Soffioni seen from Monte Oebero. Looking 8. by #, 
Lardarello ere seen three-fourths of a mile off. 
b 
a,a, Alberese and macigno. b. Gabbro rosso. 
younger marls. But whilst these rocks flank the fissure on the 
W.., it is quite oy as were said, to Monte Cerboli and 
its hot springs on the N. by W.: it also leads through undu- 
lating ground to Bagni a Morbo, ater a mile distant to the 
3. by E., where hot mineral waters also exist. The present 
lagoni are artificially formed on those points where water and 
earth are applied to the escapes of the intensely hot vapors. Par- 
tially repressing the issue of heat, by throwing on earth and clay, 
and thus controlling the size of the orifices, human agency forms 
active mud volcanoes, the number of which and their successive 
Sobestictn are regulated at pleasure. From the limited space in 
this valley of Lardarello, so irrigated and operated upon, various 
columns of vapor are seen rising to different altitudes, at differ- 
ent degrees of intensity. This perforated ground is in a contin- 
ually chaotic state from the countless changes it undergoes ; and. 
its outlines are indeed so constantly varying by the formation of 
2 fresh outlets of gas, that the traveller who should venture = 
pose 
jon. Throwing up large globules from its Rbbive pe, the 
heated matter is ever making an effort to overflow the rim of the 
little crater.* Wherever the subterranean vapor escapes from 4 
* In his description of the Hawaiian Islands of the Pacific, Mr. Dana accounts for 
the absence of active rn a and projection of materials into the atmosphere, by 
the the chief crater, in which the molten matter having a Vv 
wide vent, undulates with little or no noise, and quietly ome its —_ from time 
to time. [To this cause, as even o cause of ~ 
oer eee ctr Da ay the pra Say of eae 
