of Experimental Pbilofophy, 349 



fince been fhewn that the jarring decifions of 

 thofe learned men, were owing to the difference 

 in the a(ftion of boiling water on the feveral 

 kinds of glafs employed. Contradiclory opinions 

 are now held, by two very celebrated chemifts, 

 concerning the nature of fteel ; one afierting 

 that its phlogifton is augmented, the other that 

 it is diminifhed, in the procefs by which it is 

 made. Both appeal to experiment in fupporc 

 of their opinions ; and as the point in difpute 

 is of importance to the arcs, it merits a more 

 compleat and fatisfaftory inveftigation. 



To thefe examples I fhall add another, in which 

 I have myfelf been particularly interefted. The 

 Rev. Dr, Hales, whofe experimental inquiries 

 •were generally direfled to the good of his fellow- 

 creatures, difcovered a lithontriptic power, in 

 certain fermenting mixtures. But he acknow- 

 ledges the impradlicability of injefting fuch 

 mixtures into the bladder, with fufficient fre- 

 quency, to difiblve the (lone ; and recites his 

 experiments chiefly v/ith a view to engao-e others 

 in the fame laudable and important purfuit. The 

 fubjed however funk into oblivion, and no fur- 

 ther attempts of this kind were made, till the 

 notice of the public was again excited towards 

 the properties and ufes of fa6titious air, by the 

 writings of various learned and ingenious men. 

 At this time (1774) Dr. Saunders, a phyfician 

 in London, eminent for his knowledge of che- 



miftry. 



