460 Dr. IFall on AtlraEiion and Repulfion. 



attraftion of thefc two metals to mercury is much 

 weaker, than that of the perfeft metals, and does 

 not, for fome time, overcome the attraftion of the 

 mercurial particles inter Je -, therefore the glo- 

 bule preferves its form longer. As I believe 

 it will be admitted by every body, that no re- 

 pulfive power operates between mercury and 

 cither of the four metals, which I have men-, 

 tioned ; I think, it will alfo be admitted, that 

 the phenomena, to which I have alluded con- 

 cerning them, may be fatisfaftorily explained 

 upon the principles of my hypothefis. And if 

 this hypothefis applies fo well in thefe inftances, 

 it is allowable to extend it to other fimilar fads, 

 concerning the powerful or weak aiftion of merr 

 cury on other metals, and even to transfer it to 

 explain the appearances, which other fluids pre? 

 ient in parallel circumftances. From this ex- 

 ample then I am induced to conclude, that the 

 attraction of the particles of any fluid inter fe is 

 the caufe, why that fluid forms itfelf into glo- 

 bules, when it is in contad with another fub- 

 ftance of any kind, to which that fluid has no 

 chemical affinity or attradion, and thus may 

 give that appearance of abhorrence or repulfion, 

 by which chemifl:s have hitherto been perfuaded 

 to adopt the idea of a repulfive principle, op- 

 pofed to that of attradion. Remember, that I 

 am here fpeaking folely of chemical phenomena. 

 I dp not pretend to touch upon mechanicai, 



niagnetical^ 



