450 Z5r. Perdval on Jttra^wi and Repuffto^ 



tad of the water left behind, contrary to theif 

 mutual affinity, as well as to the law of gravita-> 

 tion. The particles of quickfilver, like water, 

 are attraaed by glafs. For if a fmall globule 

 of this metal be laid upon unfullied paper, and 

 touched with a piece of ^lean poliOied glafs, the 

 quickfilver will adhere to the latter, in prefer- 

 ence to the former, and may be drawn away 

 with it. But the relation O'f mercury to glals is 

 of inferior force, to that which fubfifls between 

 its own particles. This will appear by dipping 

 a bent tube, open at both ends, into a veflel, 

 tilled with quickfilver, which will enter into 

 the tube, but fl:and within it, below the furface 

 of the mercury, at a depth, proportionate to 

 the diameter of the tube. * It is unnecefifary to 

 adduce further inftances of this attradion; and 

 I (hall endeavour to (hew, that where it does 

 not fubfid, a repulfive pov/er apparently takes 

 place. This, according to the laws of optics, 

 has been deduced from the globules of rain, 

 which lie on the leaves of colewort, whole luftre 

 and mobility are fo ftriking to the eye. For, 

 on a clofe infpeilion of them, it is found, that 

 the luflre is produced by a copious reflection of 

 light, from their flattened inferior parts. It has 

 alfo been further obferved, that when a drop 



* Confalt Dr. Jurin's Experiments, Philofophical 

 Tranfaftions, No. 363} alfo Coles's HydroRatical Lec- 

 tures, p. 231. 



rolls- 



