CORRESPONDENCE OF RAY. 171 



Mr. BAY to Dr. ROBINSON. 



SIR, Last post brought me yours of May 19. In 

 answer whereto, seeing what you assert concerning the 

 transmutation mentioned may be true, and is supported 

 by good authority, and your opinion, I see no reason it 

 should be struck out ; for those principles into which 

 bodies are immediately resoluble by fire, being not pri- 

 mary but compound bodies, it may consist with my 

 opinion of certain and fixed first principles well enough. 



Reading in the ' Philosophical Transactions' of March 

 last yoJtf observations on subterraneous streams, I find 

 you mistaken in one of your conjectures concerning mat- 

 ter of fact, that is concerning that they call the burning 

 fountain [La Fontaine qne brule] near Grenoble, in 

 Dauphine, which our curiosity led us to make an excur- 

 sive journey from Grenoble on purpose to see. This 

 place is about three leagues distant from the city up the 

 river. When we came there, we were much deceived in 

 our expectation ; for, instead of a burning fountain, which 

 we dreamt of, from the name and relations of others, we 

 found nothing of water, but only an actual flame of fire 

 issuing out of a vent, or hole, in the side of a bank, 

 plainly visible to the eye, to which if you applied dry 

 straw, or any other combustible matter, it took fire pre- 

 sently. I took it to be nothing else but a little spiracu- 

 lum of a mine of coals, or some such like substance, fired ; 

 and my reason was, because the bank, out of which the 

 flame issued, looked much like slate and cinder of coals. 

 One thing 1 cannot but admire, that is the long continu- 

 ance of this burning. I find mention of it in ' Augustine 

 de Civitate Dei,' lib. i, cap. 7. " De fonte illo ubi faces 

 extinguunter ardentes et accenduntur extincta3 non inveni 

 in Epiro qui vidisse se dicerent, sed qui in Gallia similem 

 nossent, non longe a Gratianopoli civitate ;" by which 

 relation of the good father, we see how he was abused 



