WRITINGS OF JAMES SMITH80N. 95 



field of discovery has thus remained where otherwise it 

 would have been exhausted. 



Fluor spar has decorated mineral cabinets from probably 

 the earliest period of their existence ; every tint with which 

 chance can paint it; each casual diversity of form and 

 appearance under which it may present itself have been long 

 familiar, and its true nature continues a problem; and its 

 decomposition by fire was yet to be learned. 



Fluor Spar. 



If a very minute fragment of fluor spar is fastened by 

 means of clay* to the end of a platina wire nearly as fine as 

 a hair, which is the size I now employ even with fluxes, it 

 will be perceived on the first contact of the fire to melt with 

 great facility. As the fusion is prolonged, the fusibility will 

 decrease; protuberances will rise over the surface of the 

 ball ; it will put on what is designated by the term of the 

 cauliflower form ; and finally become entirely refractory. 

 On detaching it from the wire, it will prove hollow. This 

 little capsula being taken up again by its side, and its edge 

 presented to the flame, thin* and porous as this edge is, it 

 will withstand its utmost violence. 



Such an alteration of qualities proclaims an equal one of 

 nature. I had no doubt that the calcium had absorbed oxy- 

 gen, and parted with fluorine; that the mass had ceased to 

 be fluor spar, and was become quicklime. On placing it in 

 a drop of water my conjecture was confirmed ; a solution 

 took place by which test papers were altered ; a cremor calcis 

 soon appeared; and on allowing the mixture to become 

 spontaneously dry, a white powder remained, which acids 

 dissolved with eflervescence. 



That the fluoric element was gone admitted not of doubt. 

 To pursue it in its escape ; to coerce it, and render it palpa- 

 ble to the senses, could not be required to establish the fact 

 It may, however, be done. 



* Annals for December. 



