ggO UNUSUAL ARRANGEMENT OF STRATA. 



fected with explosion. Otherwise the communication will 

 take place slowly and gradually. 



Let us suppose, that the portion of the atmosphere over 

 a lofty peak, as Mount Blanc, be electrified positively with 

 respect to it; that is, contains more of the electric fluid: 

 it will communicate its electricity to the mountain, either 

 by flashes of lightning*, or slowly and gradually, and 

 this electricity will pass from this lofty peak to the adjacent 

 parts. 



Let us suppose on the contrary a mountain like Etna, 

 the vapours of which, ascending Constantly from its inter- 

 nal fires, are loaded with positive electricity, which they 

 take from the bosom of the mountain : the body of this 

 j^eak must be in an habitual state of negative electricity, 

 with respect to the parts of the earth contiguous to it. 



VI. 



Arrangement of the Strata of the Hill of Durbuy, in the 

 . Department of the Sambre and Meuse ; by J. J. Omalius 



DE HALLOY*. 



Arrangement JL HE examination of the different arrangement of the 



of strata im- t , , . pi 



portantin geo- strata that constitute the globe is one ot the most mterest- 



io £7« ing points of geology. Indeed till the existence of strata 



was suspected, this science did not begin to free itself from 

 the chimerical forms, in which it was retained by absurd 

 hypotheses framed on metaphysical abstractions, and take 

 its place among the physical sciences founded on observa- 

 tion. The great book of Nature cannot be too frequently 

 consulted ; but as the ablest men have it not in their power 

 to turn over all its pages, part of the task must devolve to 

 subordinate labourers, who note down every thing that ap- 

 pears to them worthy notice, at the hazard of busying them- 

 selves about things of little importance. 

 Precipitates ar- In the present state of things, every substance precipi- 

 range them* tated from a fluid in successive periods will arrange itself 



* Stones vitrified by flashes of lightning are found oa Mount Blanc, 

 t Journal des Mines, vol. XXI, p. 475 



in 



