204 GREAT PRESSURE OF WATER. 



corked, and sunk by means of weights to a considerable 

 depth in the sea, the pressure of the surrounding water 

 will either break the bottle, or force the cork into it 

 through the neck. On drawing up the bottle, it will 

 be found to be filled with water, and to have the cork 

 within it below the neck. 



This was verified by the late Rev. J. Campbell, in 

 his voyage homeward from the Cape of Good Hope. 

 He forced a cork into the neck of a bottle, so thick as 

 to fit it very tightly, and so that half the cork remained 

 above the edge of the neck ; a cord was then tied round 

 the cork, and fastened to the neck of the bottle, and the 

 whole was covered with pitch. When the bottle was 

 sunk to the depth of about fifty fathoms, it was sud- 

 denly felt to have increased in weight, and on being 

 drawn up, the cork was found inside, and the bottle 

 filled with water. At only the depth of fifty fathoms 

 the water had forced in the cork and filled the bottle. 



In another experiment a bottle was similarly corked, 

 but a sail needle was passed through the cork across 

 the edge of the neck, so as to resist the passing of the 

 cork into the bottle. It was now immersed to the depth 

 of fifty fathoms ; the same sudden increase of weight 

 was felt, and on drawing up the bottle it was found to 

 be filled with water, but the cork was not displaced. 



