1 7 i JinaJyJis of the. Air. 



will give us. How rational this method is, 

 the fequel of thefe Experiments will (hew. 



The illuftrious Sir Ifaac Newton (query 

 31ft of his Opticks) obferves, That " true 

 << permanent Air arifes by fermentation or 

 « c heat, from thofe bodies which the chy- 

 " mifts call fixed, whofe particles adhere by 

 " a ftrong attraction, and are not therefore 

 u feparated and rarefied without fermenta- 

 <c tion ; thofe particles receding from one 

 " another with the greater! repullive force, 

 iC and being mod difficultly brought toge- 

 " ther, which UDon contadl were mod 

 u ftrongly united." And, query 30. <c Denfe 

 <c bodies by fermentation rarefy into feveral 

 " forts of Air ; and this Air bv fermen- 

 <l tation, and fometimes without it, re- 

 <c turns into denfe bodies." Of the truth of 

 which we have evident proof from many of 

 the following Experiments, viz. 



That I might be well allured that no part 

 of the new Air which was produced in di- 

 ftillation of bodies, arofe either from the 

 greatly heated Air in the retorts, or from 

 the fubftance of the heated retorts, I firft 

 gave a red hot heat both to an empty glafs 

 retort, and alfo to an iron retort made of a 

 musket barrel 5 when all was cold, I found 



the 



