z6o Hints for the Formation af 



lo. Whether it does not cool more ■flowly, and according 

 to other laws, than that of the bodies heated or melted in 

 our furnaces. 



10. A. Can it be fuppofed that the matter thrown up 

 by volcanoes was not inflamed, or even in a ftate of incan- 

 defcence, in the bowels of the earth ; and that it is only the 

 contaft of the air which gives it thefe qualities ? 



11. Whether the fudden cooling of lava in the air or in 

 water divides it into prifmatic columns, fuch as thofe of 

 bafaltes. 



13. Whether it be true that fcoria ne\vly thrown up, and 

 fuddenly cooled by its rapid paflage through the air, feems 

 covered with a bituminous vaniifli. 



13. And, in general, whether the mountain throws up 

 bituminous matter or any thing that refembles the refiduum 

 of the combo (lion of coal, or whether it rather throws up 

 pyrites or the refiduum of their decompofition. 



14. To afcertain by obfervations, and even by experi- 

 ments, whether it may not be poflible that pyrites or other 

 ferru<yinous matters decompofed by water, undergo a fer- 

 mentation, which, afting on grand mafles, may difengage a 

 fufficient heat to produce the cfiefts of a volcano. 



15. Or whether, as M. Romme thinks, the fire of volca- 

 noes is kept up by matters accumulated by rivers and cur- 

 rents of the fea. 



16. To fcarch for means of afcertaining the depth of the 

 focus of the volcano. 



17. To examine whether, at the moment when an erup- 

 tion begins to take place, there is any remarkable change in 

 the tides, currents, fprings, and the neareft fpiracles and 

 volcanoes. 



18. Muddy eruptions : their height, bulk, nature of the 

 water they contain ; whether it be faline : nature of the earth 

 and ftones thrown up j whether it contains fea fhells, of what 

 kmds, and in what ftate. Watery eruptions : the fame re- 



^ fearches : 



