52 WRITINGS OF JAMES SMITHSON. 



substance, in appearance similar to ulmin, but on adding 

 water to this dry mass, a large quantity of brown glutinous 

 matter remained insoluble. The mixture being thrown on 

 a filter, a clear yellow liquor passed, which may have con- 

 tained ulmin, but the quantity was too small to admit of 

 satisfactory conclusions. 



Perhaps older wood, the juice of which was more per- 

 fected, would afford other results, since ulmin appears to 

 be the product of old trees ; but the inquiry, being merely 

 collateral to the object 1 had originally in view, was not 

 persevered in. 



ON A SALINE SUBSTANCE FROM MOUNT 

 VESUVIUS. 



From the Philosophical Transactions of the Eoyal Society of London r 

 Vol. CIII, Part I, 1813, p. 256. Read July 8, 1813. 



It has very long appeared to me, that when the earth is 

 considered with attention, innumerable circumstances are 

 perceived, which cannot but lead to the belief, that it has 

 once been in a state of general conflagration. The exist- 

 ence in the skies of planetary bodies, which seem to be 

 actually burning, and the appearances of original fire dis- 

 cernible on our globe, I have conceived to be mutually cor- 

 roborative of each other ; and at the time when no answers 

 could be given to the most essential objections to the 

 hypothesis, the mass of facts in favour of it fully justified, 

 I thought, the inference that our habitation is an extinct 

 comet or sun. 



The mighty difficulties which formerly assailed this 

 opinion, great modern discoveries have dissipated.^, Ac- 

 quainted now, that the bases of alkalies and earths are 

 metals, eminently oxydable, we are no longer embarrassed 



