76 ON THE NON-PERMEABILITY OF GLASS BY WATER, 



influence through this substance might, perhaps, be considered as 

 sufficient evidence of such structure. A more accurate statement of 

 the object of these experiments, therefore, would be to prove the 

 imj)ermeability of glass by water under high degrees of pressure. — 

 Were it possible for glass balls to resist the sudden exi)ansion and 

 heat of steam, the proof required would be more probably attained 

 by the tenuity of the elastic vapour of water, than by the same fluid 

 under the most severe pressure. 



In one of BIr. Rudder's experiments, it was observed that the 

 cork had been forced into the bottle, and was seen floating on the 

 surface of the water which half filled the bottle, and upon replung- 

 ing the bottle to the same depth, 112 fathoms, the vessel filled 

 and the cork w^as replaced. The replacement of the cork as origi- 

 nally inserted, or reversed, so far as position is concerned, is purely 

 accidental; w^hen the cork, by equal pressure, has been so far re- 

 duced in all its dimensions that either end of it would enter into 

 the neck of the bottle, that part would be certain to be uppermost, 

 which presented itself to the neck, during the ascent of the bottle. 



It may not, perhaps, be considered altogether irrelevant to the 

 present subject, to allude to the astonishing power of the whale to 

 resist pressure. When struck with the harpoon, the whale dives 

 perpendicularly, and the quantity of line they sometimes take out of 

 the boat, in a perpendicular descent, Captain Scoresby considers a 

 good measure of the depth. By this rule, they have been known to 

 descend a mile ; bearing, consequently, a pressure of one ton and a 

 quarter on every square inch ; which multiplied by the extent of 

 surface of the animal, varying in length from 60 to 200 feet, and of 

 proportionate width, gives an amount almost incredible — 720,000 

 tons ! 



It is very reasonable to enquire if there be any provision in the 

 structure of diving animals, to enable them to sustain such pres- 

 sure. In a paper read by Mr. Houston, at the late Meeting of 

 the British Association, "On Peculiarities in Circulating Organs 

 of Diving Animals," it was observed that circulation, though 

 principally carried on and continued by the vital principle, and 

 ceasing altogether when that principle becomes extinct, was to 

 some extent amenable to the laws of hydraulics. 



