Captain Edward Sabine on the temperature , &c. 207 
water of any detached portions of the main ocean within the 
tropics ; whilst however the connection is preserved, and by 
deep sea channels, it could scarcely be doubted, that if the 
colder water of distant regions finds its way to the equatorial 
parallels of the main ocean, it would no less pervade the 
corresponding depths in the same parallels, wheresoever a 
communication existed to admit its passage : if such an opinion 
required confirmation, it appears to have received it by the 
result of the present experiment. 
A transcript of the memorandum which I wrote at the 
time, may probably be deemed the most satisfactory mode 
of relation. 
“ H. M. S. Pheasant, on passage between Grand Cayman 
Island and Cape St. Antonio, in Cuba, lat. 2o|- N. Ion. 83 % 
W., November 13th, 1822. 
“ At 2 P.M. hove too, and sounded with 1230 fathoms of 
line, being 11 coils of 113 fathoms each, and three fathoms 
of a 1 2th coil ; at the end of the line was attached a strong 
iron cylinder of 75 lbs. weight, enclosing a Six’s self-regis- 
tering thermometer : the top of the cylinder screwed down 
upon leather, being designed, by excluding the water from 
the interior, to obviate any effect which might be supposed 
to arise from the increased pressure of water at great depths : 
the thermometer fitted into spiral springs at the top and bot- 
tom, which kept it from contact with other parts of the cy- 
linder, and preserved it from injury, in case the apparatus 
should accidentally strike against the sides of the ship, or 
against rocks at the bottom : another iron cylinder, of much 
less strength and weight than the preceding, was attached 
two fathoms above the end of the line, and being pierced 
