16 



the Gulf Stream when they flow toward the 

 north. The ship boys amuse themselves with 

 cutting off a part of the pectoral fins, and assert, 

 that these wings grow again ; which seems to me 

 not unlikely, from facts observed in other fami- 

 lies of fishes. 



At the time I left Paris, experiments made at 

 Jamaica, by Dr. Brodbelt*, on the air contain- 

 ed in the natatory bladder of the sword-fish ^ 

 had made some naturalists think, that under the 

 tropics, in the sea fish, this organ was filled 

 with pure oxygen gas. Full of this idea, I was 

 surprised at finding in the air-bladder of the fly- 

 ing fish only 0*04 of oxygen to 0*94 of azot and 

 0*2 of carbonic acid. The proportion of this last 

 gas, measured by the absorption of lime water in 

 graduated tubes J, appeared more constant than 

 that of the oxygen, of which some individuals 

 yielded almost double the quantity. From the 

 curious phenomena observed by Mr. Biot, Con- 

 figliachi, and Delaroche §, we might suppose, 

 that the sword-fish dissected by Dr. Brodbelt 

 had inhabited the lower strata of the ocean, 



* Duncan's Ann. of Medicine, 1790, p. 393. Nicholson's 

 Journ. of Nat. Phil., 4to. ed., vol. i,p. 264. 

 f Xiphias gladius. Lin. 



X Anthracometers, curved tubes with a large ball. See 

 my Essays on the atmosphere, plate 1 (German) . 



§ Mem. d'Arcueil, vol. i, p. 257. Ann. du Mus. t. 14, 

 p. 184—217, and 246—280. Configliachi sull' Analisi dell 



