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tuff, extending for four miles along the coast, and forming 

 cliffs more than 200 feet high, have been discoloured in various 

 places, and strangely altered by the " all-penetrating vapours." 

 Dark clays have become yellow or often snow white, or have 

 assumed a chequered or brecciated appearance, being crossed 

 with ferruginous red stripes. In some places the fumeroles 

 have been found by analysis to consist partly of sublimations 

 of oxide of iron ; but it also appears that veins of chalcedony and 

 opal, and others of fibrous gypsum, have resulted from these 

 volcanic exhalations. M. Virlet gives an account of the 

 corrosion of hard, flinty, and jaspideous rocks near Corinth by 

 the prolonged agency of subterranean gases, and Dr. Daubeny 

 describes the decomposition of trachytic rocks in the Solfatara 

 near Naples, by sulphuretted hydrogen and muriatic acid gases. 

 Although in all these instances we can only study the 

 phenomena as exhibited at the surface, it is clear that the 

 gaseous fluids must have made their way through the whole 

 thickness of porous or fissured rocks which intervene between 

 the subterranean reservoirs of gas and the external air. The 

 extent, therefore, of the earth's crust which the vapours have 

 permeated and are now permeating may be thousands of 

 fathoms in thickness, and their heating and modifying influence 

 may be spread throughout the whole of this solid mass. "We 

 learn from Professor Bischoff that the steam of a hot spring at 

 Aix-la-Chapelle, although its temperature is only from 133 to 

 167 F., has converted the surface of some blocks of black 

 marble into a doughy mass. He conceives, therefore, that 

 steam in the bowels of the earth, having a temperature equal to 

 or even greater than the melting point of lava, and having an 

 elasticity of which even Papin's digester can give but a faint 

 idea, may convert rocks into liquid matter. These wonderful 

 facts might suggest useful thoughts to the despots of the world. 

 Despotism interdicts the expression of political convictions, and 

 seeks to bury them under the adamantean weight of oppressive 

 decrees and colossal cruelty. But it is an unerring moral law 

 that the warm aspirations of a virtuous people shall like the 

 subtle subterranean gases arise to freedom, and despite all 

 impediments, dissolve in due time even the hard and hoary 

 foundations of injustice. B. 



