relating to Air and Water* 305 



Willing to try the efFeft of heating iron, and other fub- 

 flances, in all the different kinds of air, without any particular 

 expe£lation, I found that iron melted more readily in vitriolic 

 CiCid air than in dephlogifticated air, the air was diminiflied as> 

 rapidly, and the infide of the veffel was covered with a black 

 footy matter, which, when expofed to heat, readily fublimed in 

 the form of a white vapour, and left the glafs quite clean. 

 The iron, after the experiment, was quite brittle, and 

 mufl, I prefume, be the fame thing with iron that is fid- 

 phurared; but I did not particularly examine it. Of feven 

 ounce meafures of vitriolic acid air, in one of thefe experi- 

 ments, not more than three-tenths of an ounce meafure re- 

 mained ; of this two-thirds was fixed air, and the refiduum 

 of this was inflammable. I had put three of fuch refiduums 

 together, in order to make the experiment with the greater 

 certainty. 



Having tranfmitted ^^<3W, or the vapour of water, througlr 

 a copper tube, I was willing to try the effects oi fpirit of wine 

 through the fame tube when red-hot, having before procured 

 inflammable air by fending the fime vapour through a red-hot" 

 tobacco-pipe^ In this cafe, the vapour of the fpirit of wine- 

 had no fooner entered the hot copper tube, than I was perfedly 

 sftoniflied at the rapid produ6llon of air. It refembled the 

 blowing of a pair of bellows. But I had not ufed four ounces-" 

 of the fpirit of wine before I very unexpectedly found, that 

 the tube was perforated in feveral places; and'prefently after- 

 wards it was fo far deftroyed, that in attempting to remove itr 

 from the fire it aftually fell in pieces. The inlide was full of a 

 black footy matter refembling lamp-black. 



Upon this. I had recourfe to earthen tubes ^ and found, that by 

 melting coppfe'r and other metals in them, and tranfmitting the 



Vol, LXXV* R x vapour 



