296 On the Adhesion of the Particles 



poured a stratum of water of three lines in thickness 

 upon the mercury, and upon that a stratum of ether of 

 two lines. 



When the whole was at rest, I took with the small 

 tool before described a spherule of mercury of about one 

 third of a line in diameter, and let it fall through the 

 stratum of ether. 



This spherule, being too heavy to be supported by the 

 pellicle at the superior surface of the water, broke it, and 

 descended through that fluid ; but upon its arrival at 

 the inferior surface it was stopped, and remained there, 

 preserving its spherical form. 



I moved this spherule with the extremity of a feather, 

 and even compressed it; but it always preserved its 

 form without mixing with the mass of mercury on which 

 it appeared to rest. 



It was no doubt the pellicle of the inferior surface of 

 the stratum of water which prevented this contact, and 

 as this pellicle was supported by the mercury on which 

 it rested, I was not at all surprised to find that it could 

 support, without being broken, a spherule of mercury 

 much larger than the pellicle of the superior surface 

 could support. 



In order to satisfy myself that the viscidity of the 

 water was the cause of the suspension of this mercurial 

 globule at the bottom of that fluid, I repeated the ex- 

 periment and varied it by substituting water containing 

 a certain quantity of gum-arabic, in solution, in the 

 place of pure water ; and I found, in fact, that much 

 larger spherules were supported when the viscidity of 

 the water was thus augmented. 



To prove this fact in another manner, I again varied 

 the experiment, by placing a stratum of ether im- 



