, [ 423 3 



XIX. Ohjervat'ions on Pumice Stone, and (he Placeif luheu 

 found. By ProfejO'or Beck M Ann*. 



P 



-*- UMICE ftone, prntiex, furrc-ponce, pomtce, is a porous, 



light, friable, rough kind of ftone, which floats in water ; 

 neither ilrlkes fire with fteel, iior effervefces with acids j 

 contains little or no iron, but fometimes more, fometime,s 

 Icfs niagnefia ; and, in a ftrong heat, becomes fufed to glafs 

 without the addition of any other fubftance. On account 

 of its lingular properties, an idea was entertained, even in 

 the moft ancient periods, that it muft have originated in a 

 different manner from other ftones. As it was found in 

 many parts floating on the fea, the ancients confidered it to 

 be a kind of hardened fea-fcum ; as from the fame fuper- 

 ficial grounds the bones of the cuttle-fifli, employed for 

 many purpofes like pumice ftone, are called fea-fcum alfo. 

 More attentive obfervers, however, perceived that it was in- 

 debted for its formation to the force of fire ; efpecially as it 

 was found, for the moft part, near volcanoes, and was ac- 

 tually thrown up by them. 



It is now known with certainty, that real pumice ftone is 

 a volcanic production, both that thrown up by the fea, and 

 that found even in Germany, where there are no burning 

 mountains. The latter kind is a proof that in thcfe dif- 

 tricls there muft formerly have been volcanoes ; and the 

 former, of volcanoes fo near the fea that their eruptions 

 could reach it. No place, however, abounds more with 

 this. kind of ftone than the Lipari iflands, particularly Lipari 

 and Vulcano, from which, fince the earlieft periods f, all 

 JEuropc has been fupplied with this ftone, and ohiefly by the 



'■ A chemical cxdmination of it m-iy be found in Carthcufcr's Mir.era- 

 iQ^iicd F.ffays ; Kcrgmann's Opufiiila, III. p. 197 ; and Achard's Collciiion 

 of I'hyfiLul and Chaaical EJfays, I. p. 50. 



•t Pumices IzudatiflJmi funt in j'Eoliis inrjHs, Plin. H'Ji. Kit. lib. 

 Kxxvi. cap. J I. 



Ee^j, Sicilians. 



