of Water to each other. 293 



All the preceding experiments were repeated with 

 a stratum of essential oil of turpentine, and afterwards 

 with one of oil of olives, placed on the water contained 

 in the glass instead of the ether, and the results were 

 in all respects similar. I thought, however, that the 

 spherules of mercury which were suspended "upon the 

 water were rather larger when the surface of the water 

 was covered with oil than with ether ; and in the ex- 

 periments made with the powder of tin poured on the 

 oil, the finest parts of the powder in very small quan- 

 tity floated on the surface of the oil. 



Experiment No. 4. Having found means to place a 

 stratum of alcohol on the water contained in the glass, 

 so that the two liquids appeared as distinct from each 

 other as when the upper stratum was oil, I poured 

 from a very small height a small quantity of the very 

 fine powder of tin upon the alcohol. 



This powder totally descended through the alcohol 

 and the water, without giving the smallest indication of 

 its having been subjected to any resistance at the sur- 

 face of the latter fluid. 



Though this last surface appeared very distinctly to 

 the eye, yet, judging from the manner in which the 

 metallic powder descended to the bottom of the glass, 

 I am disposed to think that it had no existence ; and, in 

 fact, it is probable that it was destroyed by the chemical 

 action of the alcohol in contact with the water. 



In order to examine more accurately the kind of film 

 which is formed at the surface of the water, I made the 

 following experiment. 



Experiment No. 5. In a cylindrical glass with a solid 

 foot, the diameter of which was fourteen lines, or about 

 an inch and a half English, and ten inches in height, I 



