"Dr. Wall on AttraEilon end 'Repulfion. 4^5 



fittracllon to fubftances, which contain a laro-e 

 proportion of phlogifton. Exceptions might 

 be brought to this pofition, but thefe might 

 be fo eafily obviated, that the fad may be 

 admitted as general. Metals particularly ex- 

 emplify this point; efpecially if they are highly 

 polifhed, when their furface Is fo perfevflly clean, 

 that all thdfe properties, which depend upon 

 the phlogifton, are mod obvious and percepti- 

 ble. If water be poured upon a metal in this 

 ftate, it is with difficulty made to wet the fur- 

 face, but runs off immediately; or if it adheres 

 it adheres in a difcontinued and broken manner. 

 Iron, when wrought to the high temperature of 

 lieel, peculiarly exhibits this appearance. And 

 fomething of the fame kinci may be fuppofed to 

 obtain, when a fmall piece of highly polifhed 

 iron, fuch as a needle, is laid upon water. Hence 

 the needle, though it is fufpended on the furface 

 of the water, yet does not, except perhaps in the 

 very lowea part of it, touch the water, but in a 

 few points. 



After all, 1 would have it perfeflly underftood, 

 that I by no means prerend to deny the fafls, 

 ^hich feem to evince a repulfive principle; 

 but only prefume to offer my opinion, that in 

 chemiftry, thefe fads may "be explained by the 

 dodrine of fuperior elcdive attra6tion, with- 

 out the neceffity of introducing more principles 

 or caufes, than the fads fcem to require, 



I am 



