Dr. Percival on Attramon and Repulfion. 449 



jpremifing a few obfervations on that fpecies of 

 attramon, which appears to be the converfe of it. 

 III. That the particles of homogeneous bodies 

 Jiave an affinity to, and confequcntly attrad: 

 each other, is confonant both to analogy and 

 obfervation. Fluids manifeft this property, by 

 their difpofition to alTume a globular figure, 

 and by the rufhing together of thefe globtles* 

 when brought within their reciprocal Inhere of 

 aaivity. A fimilar attraftion fubfifts between 

 heterogeneous fubllances, which is diftind from 

 that of cobefion, as it partakes of an eUmve na- 

 ture, and yet cannot be deemed chemical, becaufe 

 no combination is produced by it, fo intimate, 

 as to manifeft any change of properties. This 

 may be illuftrated by the increafe of power, in 

 the fufpenfion of weights, which a hair acquires, 

 by being moiftened with different liquids. For 

 fuch additional ftrength is not proportioned . 

 precifely, to the tenacity of the liquid employed,* 

 and probably fubfifts in a duplicate ratio, com« 

 pounded of the affinity which the parts of the 

 liquid bear to each other, and to the minuteft 

 fibres of the hair. The particles of water attrad: 

 one another more ftrongly, than they attradt 

 poliffied wood or ftonej whilft, on the contrary 

 they are lefs forcibly attrafled by each other 

 than by gjafs. This is evinced by the common 

 experiment with capillary tubes. For the wa- 

 ter, which afcends, muft have quitted the con- 

 ^°^- "• G g udl 



