190 ACCOUNT OF THE ARCTIC REGIONS. 



persons have imagined that even lead cannot sink* 

 but will bt' suspended mid-way in the sea ! I have 

 conversed, indeed, with very intelligent persons^ 

 who could not be persuaded that any dependence 

 could be placed on soundings obtained at a depth 

 exceeding 300 fathoms. Were water a compressi- 

 ble substance, like air, it would be possible, that, 

 under a certain pressure, it might become as heavy 

 as lead ; so tliat lead, or any other ponderous body, 

 could only sink to a certain depth ; but water being- 

 incompressible, or nearly so^ it is clear, however great 

 the pressure may be, that it must be the same down- 

 ward as upward, on any body suspended in it ; conse- 

 quently, bodies specifically heavier, will continue to 

 gravitate downward, whatever be the depth, or the 

 weight of the column of water above them. 



The difficulty of getting satisfactory soundings, 

 at great depths, arises, principally, from the uncer- 

 tain intimation given, when the lead strikes the 

 bottom. This uncertainty is increased by using a 

 tlrick line : for, if a lead of a hundred pounds weight 

 were used, the rope attached to it would require to 

 be so thick, that, at the dqjth of six or eight hun- 

 dred fathoms, the weight of the line, even in water, 

 would be so many times greater than that of the 

 lead, that scarcely any effect could be observed 

 when it should reach the bottom. Hence I always 

 prefer a light lead, and a very small line. With a 

 lead of 20 pounds, I have sounded in above 1000 



