VICIDITY OF WATER. 53 



fluid. Such for example, are very small grains of sand, specific gravity- 

 may flc 

 water. 



fine filings of the metals, and even small sewing nee- J"^^J^"^^ ^'^ 



dies. 



So extraordinary a phenomenon haf: not failed to ex- 

 cite the attention of philosophers. It formed a subject 

 of discussion at the last sitting of the Class, and as this re- 

 markable fact is intimately connected with a subject of 

 research upon which 1 have been long employed, I shall . 

 here give an account of some experiments I have made to 

 elucidate the same, and have aiforded results of consider- 

 able interest. 



Suspecting that the presence of air adhering to these This effect at- 

 small floating bodies, which is generally considered as the tributed to air. 

 cause of their suspension, is not indispensably necessary 

 for the success of the experiment, I made the following : 

 EXPERIMENT 1. 



Having half filled with water, a wine glass one inch and Ether was 



a half diameter at its edge, I poured on the surface of poured upon 

 - » , , . , . 1 , water. Small 



the water a stratum of sulphuric ether, one inch and a bodies descend- 

 half in thickness ; and when the wnole was perfectly still, ed through the 

 I took a very small sewing needle with a pdir of pincers, ed^on^the wa-^ 

 which I introduce'd below the ether, where holding it ter. 

 horizontally at a small distance from the surface of the 

 water, I let it fall. The needle descended to the water 

 and there floated on its surface. 



EXPERIMENT II. 

 Hating melted^ some tin I poured it into a spherical Granulated tin 



wooden box, and shaking it strongly, the metal in cool- cle^cended 



It f .. 1 , ... through the 



ing was reduced to powder which was then sifted. surface of the 



On examining this powder with a magnifier, it appear- ^^her and rest- 

 ed composed of small spherules of different sizes; but jj^^^^^^^^^^ °- 

 ihese spherules were too small to be distinguished by 

 the naked eye. 



I took up on the point of a spatula a very small quan- 

 tity of this metallic po,vdor, and poured it gently from the 

 height of a quarter of an inch on the surface of the ether 

 Avhich rested upon the water in the glass. 



The powder descended wholly through the ether, and 

 when it ari Ived at the surface of the water, it remained 

 Hoating. 



EXPERIMENT 



