THE XIAAL-STEOOM. 
133 
ogain ; 'which seems to me not unlikely, from facts observed 
in other families of fishes. 
At the time I left Paris, experiments made at Jamaica by 
Dr. Brodbelt, on the air contained in the natatory bladder of 
the sword-fish, had led some naturalists to think, that within 
die tropics, in sea-fish, that organ must be filled with pure 
oxygen gas. Full of this idea, I was surprised at finding in 
tne air-bladder of the flying-fish only O'Ol of oxygen to 094 
of azote and 0'02 of carbonic acid. Tlie proportion of this last 
gas, measured by the absorption of lime-water in graduated 
tubes, appeared more uniform than that of the oxygen, of 
which some individuals yielded almost double the quantity. 
From the curious phenomena observed by MM. Biot, Confi- 
gliachi, and Delaroche, we might suppose, that the sword- 
fish dissected by Dr. Brodbelt had inhabited the lower strata 
of the ocean, where some fish* have as much as 0 92 of 
oxygen in the air-bladder. 
On the 3rd and 4th of July, we crossed that part of trie 
Atlantic where the charts indicate the bank of the Maal- 
stroom ; and towards night we altered our course to avoid the 
danger, the existence of which is, however, as doubtful as that 
of the isles Fonseco and St. Anne. It would have been 
perhaps as prudent to have continued our course. The old 
charts are filled with rocks, some of which really exist, though 
most of them are merely the ofispring of those optical illu- 
sions which are more frequent at sea than in inland places. 
As we approached the supposed Maal-stroom, we observed no 
other motion in the waters than the effect of a current which 
bore to the north-west, and which hindered ns from diminish- 
ing our latitude as much as we wished. The force of this 
current augments as we approach the new continent ; it is 
modified by the configuration of the coasts of Brazil and 
Guiana, and not by the waters of the Orinoco and the 
Amazon, as some have supposed. 
From the time we entered the torrid zone, we were never 
weary of admiring, at night, the beauty of the southern sky, 
which, as we advanced to the south, opened new constella- 
tions to our view. We feel an indescribable sensation when, 
on approaching the equator, and particularly on passing from 
* Tr.igla cucullus. 
