S T. J A G O. 63 
The fine weatlier and smooth water in this part of the voyage 
gave us an opportunity of ascertaining a fact, which, though 
well known to philosophers and to -most seamen and satis- 
factorily explained on natural principles, is not by any means 
in general belief. I allude to the experiment of sinking, to a 
certain depth, an empty bottle corked as tightly as possible ; 
when the cork, on drawing up the bottle, will invariably be 
found to have been forced into the inside. We let down, to 
the depth of forty fathoms or 240 feet, a large earthen bottle 
firmly stopped with a tapering cork, so that the diameter of 
that part of it out of the bottle greatly exceeded the widest 
part of the neck ; round this was laid a coating of melted 
pitch, and the whole covered with canvas. On drawing up 
the bottle the cork was in the inside. In tropical climates 
the diminution of tem.perature, at so considerable a depth be- 
low the surface, condensing the inclosed air, takes off all 
reaction against the weight of the superincumbent cohmm of 
water pressing on the cork, and thus aids the experiment; 
but in high latitudes, where the air when corked up is pro- 
bably at the freezing temperature, whilst that below the sur- 
face of the sea is warmer by eight, ten, or twelve degrees, the 
increased elasticity, acting against the cork within, must re- 
quire the bottle to be sunk to a greater depth than in the 
former case, before the experiment can succeed. 
We were followed into Pray a bay on the island of St. Jago 
by four ships which had sailed from Dunkirk under French 
colours, and an American from Nantucket, all bound for the 
Southern Whale Fishery on the coasts of Lima and Peru ; 
having also cargoes of clothing and other articles on board, 
