Dr. Wall on AttraBion and 'Repulfion. 457 



as you do. I think your theory too fubtile. 

 What is the primary adion of atmofpheric air, 

 received into the lungs ; and what appears to be 

 jthe operation it performs there, before it is re- 

 ipired ? Do not the late obfervations of innu- 

 merable chemifts (hew, that it is in part con- 

 verted into fixed air in that procefs, and in part 

 phlogifticated, by carrying off the phlogifton, 

 feparated from the blood in the circulation, and 

 difcharged by the lungs ? The more perfedly 

 the air infpired is dephlogifticated, it anfwers 

 the demand of nature more entirely; but when' 

 it is either largely mixed with fixed air, or 

 loaded with phlogiftic particles, fuch as the 

 empyreumacic vapours from burnt oil, it is 

 rendered unfit for thefe important pnrpofes, and, 

 inftead of carrying off noxious matters, it con- 

 veys into the lungs a new caufe of offence ; and 

 thus produces a fenfe of conflid and uneafinefs 

 in a two-fold manner; by not carrying off the 

 load from which the conftitutioa is ufually freed 

 by the procefs of refpiration ; and by fuperadding 

 zjlimiilus ah extra. 



I cannot admit the application of the laws of 

 rnechanical attraction, much lefs the properties of 

 algebraic quantities, to the phaenomena of che- 

 miftry. It was well obferved by the late excel- 

 lent Dr. LevAs^ of Kingfton, in his Philofophical 

 Commerce of Arts, " that it is of great im- 

 f' portance, that thefe two orders or forms of 



" attradion 



