Mr. Smithson on a saline Substance, ^c. ftS7 



Every thing tells that a large body of combustible matter 

 still remains enclosed within this stony envelope, and of which 

 volcanic eruptions are partial and small accensions. 



Under this point of view, an high interest attaches itself to 

 volcanoes, and their ejections. They cease to be local pheno- 

 mena; they become principal elements in the history of our 

 globe ; they connect its present with its former condition ; 

 and we have good grounds for supposing, that in their flames 

 are to be read its future destinies. 



In support of the igneous origin, here attributed to the pri- 

 mitive strata. I will observe, that not only no crystal imbedded 

 in them, such as quartz, garnet, tourmaline, &c. has ever been 

 seen enclosing drops of water ; but that none of the materials 

 of these strata contain water in any state. 



a. The present saline substance was sent to me from Naples 

 to Florence, where I was, in May 1794, with a request to 

 ascertain its nature. The general examination which I then 

 made of it, shewed it to be principally what was at that time 

 called vitrioldted tartar, and it was in consequence mentioned 

 as such in an Italian publication soon after. But as this deno- 

 mination, surprising at that period, was not supported by the 

 relation of any experiments, or the citation of any authority, 

 no attention was paid to it ; and the existence of this species 

 of salt, native in the earth, has not been admitted by mineralo- 

 gists, no mention being made of it, I believe, in any minera- 

 logical work published since. 



b. I was informed by letter, that it had " flowed out liquid 

 from a small aperture in the cone of Vesuvius," and which I 

 apprehend to have happened in 1793 or 1793. 



