63 
** The longevity of the turtle, under a total abstinence from 
food, has been frequently remarked. One of ours was brought 
alive to England, and during a passage of two months, lay on 
its back upon the quarter-deck without any attention but having 
a wet swab placed under its head, and a few buckets of salt 
water dashed over its body every morning. 
* We quitted Ascension the 28th May, after remaining 
there 24 hours, and on the 2d June crossed the line in 23? 
10' under the impulse of a fine south-east trade wind, which 
followed us to about 4' north, where, after an interval of one 
day's squally weather, we took up the north-east trade. I did 
not remark while crossing the line, either on this or any of 
my former voyages, that tremendous roll of the sea, which is 
said to prevail there, and which is attributed by theoretical phi- 
losophers to the increased oscillation of the ocean necessarily 
resulting from the greater diameter of the globe at the equa- 
tor. Itwould require, indeed, no unusual powers of reasoning 
to prove, that in those parts of the ocean where the wind 
blows constantly and invariably from one point of the com- 
pass, without ever either swelling to a tempest or lulling to a 
calm, the waves can never rise to any dangerous magnitude. 
It is only during the calm that immediately follows a gale, or 
in that part of the sea which lies just beyond the sphere of its 
action, that this roll is ever remarked. It is, accordingly, in 
the latitudes of the variable winds, and off the great conti- 
nental headlands, that it mostly prevails, and in no part of 
the ocean is it of more frequent occurrence, or more alarming 
magnitude, than off the southern promontory of Africa. 
* We did not see many flying-fish or albicores until we 
crossed the line, but from thence to 22? north, we were daily 
surrounded by shoals of both. The former were of two 
species, the common .Zzocetus volitans and the E. evolans. 
The latter is larger, much less abundant, and readily distin- 
guishable during its flight by the purple colour of its pectoral 
fins. Numbers of both species, darting about in the dusk of- 
the evening, struck against the rigging and dropped on board, 
while many more, flying lower, dashed themselves against the 
sides of the vessel, and fell dead or stunned into the water. 
