in Fluids. 341 



Experiment No. ^^. 



A cake of ice, 3 inches thick, which had a pointed 

 projection, ^ an inch high, which arose from the center 

 of its upper surface, being frozen fast in the bottom of 

 a tall cylindrical glass jar, 4I inches in diameter, this jar, 

 standing in an earthen pan, and being surrounded by- 

 pounded ice and water, to the height of an inch above 

 the level of the upper surface of the cake of ice, was 

 placed on a table, near a window, in a room where the 

 air was at the temperature of 31° of Fahrenheit's ther- 

 mometer ; and fine oiive oily which had previously been 

 cooled down to the temperature of 32", was poured into 

 the jar till it stood at the height of 3 inches above the 

 surface of the cake of ice. 



Haying ready a solid cylinder of wrought iron, i^ 

 inch in diameter, and 12 inches lono;, with a small hook 

 at one end of it, by means of which it could occasionally 

 be suspended in a vertical position, and furnished with 

 a fit hollow cylindrical sheath of thick paper, into which 

 it just passed, — open at both ends, and about -^-^ of an 

 inch longer than the solid cylinder of iron, to which it 

 served as a covering for keeping it warm, — this iron cyl- 

 inder, being heated to the temperature of 210° in boiling 

 water, and being suddenly introduced into its sheath, was 

 suspended by an iron vv^ire which descended from the ceil- 

 ing of the room, in such a manner that its lower end 

 entering the jar (in the direction of its axis) was im- 

 mersed in the oil to such a depth that the middle of 

 the flat surface of this end of the hot iron, which was di- 

 rectly above the point of the conical projection of ice, 

 was distant from it only -^-^ of an inch. The end of the 

 sheath descended -^^ of an inch lower than the end of 

 the hot metallic cylinder. 



