Intelligence and Miscella?ieous Articles, 459 



well as chemical action beneath the surface of the earth, and is of 

 opinion that the gaseous products of beds of coal have assisted in 

 converting their covering of loose sand and clay into coal sandstone 

 and clay ironstone. 



As the subject of internal changes is of practical importance to 

 the miner, Mr. S. recommends its investigation. The garnets and 

 zeolites found in shale by Mr. Henslow, are decided instances of 

 internal changes, and coincide with some of the facts previously 

 noticed by Mr. S. 



His distinction between lava and trap, which we more generally 

 call Basalt, and in Scotland is chiefly known by the name of Whin, 

 is confirmed by the authority of Sir James Hall : " Calcareous spar 

 frequently occurs in whinstone, either in veins, or in detached no- 

 dules, but is never found in lava, and could not exist in a volcanic 

 stream. It is generally supposed that some lavas of iEtna contain 

 calcareous spar and zeolites; but this I conceive to be a mistake. 

 It is true I have seen that many rocks of iEtna contain these sub- 

 stances in abundance, but in my opinion these rocks are not lavas, 

 but have flowed subterraneously like our whins, and are the same 

 with them in every respect. A particular district of iEtna, com- 

 prehending the Cyclopian Isles, and the country round La Trizza, 

 and the Castle of Jaci, is decidedly of this description; and vestiges 

 of this kind occur in other parts of the mountain. In one place 

 fossil coal has been found, and in another we saw marine shells. In 

 the neighbourhood of Bronte, we observed a high ridge formed of 

 strata of sandstone and limestone, partly overflowed and concealed 

 by recent lava, but so placed as to render it evident that its con- 

 struction formed no inconsiderable part of the mountain." 



Mr. S. has heard disciples of Werner mention, that from its con- 

 tiguity to basalt, he supposed iEtna was erected on the site of a 

 coal mine: the additional coincidences in Sir James Hall's descrip- 

 tion seem to prove that coal is a part of the fuel of iEtna. Breis- 

 lack, who has spent many years in examining Vesuvius, is of opi- 

 nion that it is fed by the bituminous strata of the Appenines. 



The principal objection to this opinion has been removed by Sir 

 Humphry Davy, whose genius has been scarcely more conspicuous 

 in anticipating the discoveries made by the galvanic battery, than 

 in drawing those inferences from them which have assisted his con- 

 temporaries in bringing other discoveries to light. Thus our know- 

 ledge of the properties of iodine is a natural consequence of his 

 observations on the nature of chlorine: these and every other 

 agent of combustion ought to be enumerated in discoursing on the 

 infinite variety of chemical and electro-chemical operations which 

 may take place in the vast laboratory of Vesuvius. Since with the 

 assistance of the electrical energies of iron we can make potash 

 yield up its oxygen, is it not possible that the earths may be reduced 

 to a metallic state by a similar process in the bowels of the moun- 

 tain? These considerations show there is no necessity for any 

 contrivance or reservoir to keep up the supply of elastic oxygen. 

 By placing at the command of the philosopher powers which are 

 always close at hand, and are capable of producing tremendous 



3 N 2 results, 



