'45^ J^^* ^^^^ on AttraSfion and Repulfion. 



will abfolutely ftand the teft of examination, fa 

 far as to prove, that there is no principle of re- 

 pulfion in chemiftry : but I think ftill, notwith- 

 Handing your very ingenious obfervations, that, in 

 moft cafes, APPARENT REPULSION nnay be refolved 

 into ELECTIVE ATTRACTION. The experiment, 

 which you firft adduce, made with a mixture of oil 

 and water agitated in a glafs veffel, if I underftand 

 it right, appears to me not to affeit the point in 

 queftion. I think that the commotion, which 

 the water undergoes while the oil remains tran- 

 quil, depends upon the different fpecific gravity 

 of the two fluids (whereby they receive the force 

 of the impulfe in unequal proportions) and upon 

 the difpofition of the oil, from its fuperior levity, 

 to preferve its place, upon the top of the water, 

 whatever agitation the water benearh may be 

 fubjefled to. In the boiling of brine, I admit 

 that the agitation of the water rnuft have a roq- 

 fiderable efFefl; in breaking down the cryllals of 

 falts, and thus preventing their regular and 

 complete formation : but this cannot be all that 

 takes place, when an oily fubftance is put into 

 the brine; becaufe, if it were, the fame eflrecfl 

 would refult from boiling the brine only without 

 the addition of any oily or refinous matter. 



Forgive me, in the fecond place, if I fhould 

 not agree with you in explaining the conflid, 

 which is felt in the lungs, upon the infpiration 

 of the fumes of burnt oil, in the fame manner 



a^ 



