438 Original Articles. [July, 
Italy, where a complicated series of lavas, of various dates, penetrating 
cretaceous and tertiary rocks, is in turn penetrated by hot vapours and 
currents of water. These in one place have left behind deposits of 
copper ore, in another pure sulphur, in another lagoni or pools, saturated 
with salts of borax, while carbonic acid gas, nitrogen, and sulphuretted 
hydrogen gases issue in abundance. 
It is by the help of these gas and water currents, and in the natural 
course of operations that belong to the ordinary conditions of things, 
that the mineral veins of Monte Catini and the other mining districts 
of Tuscany have been filled, and this it is which gives the subject a 
spec:al interest and value. 
