VOYAGE OF THE * ECLIPSE.' 123 



under water. In whaler's parlance, the Finners were " span- 

 ning," i.e., appearing at regular intervals, and swimming in a 

 decided direction. Watch in hand, I found them to remain 

 under water from eight to ten minutes, and to remain at the 

 surface every time they came up to breathe from thirty to sixty 

 seconds ; their speed I estimated at about five miles per hour. 

 It is commonly believed, if I mistake not, that during progression 

 the body of the Whale describes a succession of short curves, 

 each answering to every stroke of the tail. No such acrobatic 

 feat is performed; the hinder part of the body and the fin 

 thereto attached are alone in motion, slowly but regularly, and 

 decidedly, and only in a vertical direction ; along the resultant in 

 a direct and undeviating manner the body advances forward. 

 The pectoral hmbs thus freed of their share of locomotion are 

 at liberty to act in guiding the animal, or to serve any other 

 function for which they may be adapted. The Finners I was 

 watching were never many feet imder water; they could be 

 easily followed from the moment they left the surface until they 

 again rose to breathe, the eye being greatly assisted by a peculiar 

 whitish — perhaps phosphorescent — appearance their bodies as- 

 sumed while under water. To cause them to rise to the surface 

 the great pectoral fins were slowly extended, then perhaps being 

 rotated on their axis ; the water through which they were moving 

 was thus caused to strike obliquely on their surface, — hence the 

 anterior portion of the body, being thus raised upward, the force 

 resulting from the action of the caudal fin was obviously caused 

 to act at an angle on the axis of the body, and the animal, as it 

 advanced forward, gradually approached the surface. As soon 

 apparently as the power exerted by the muscles of expiration 

 was sufficient to overcome the weight of the supercumbent 

 water respiration took place, and before the animal's head was 

 above the surface a column of breath was projected vertically 

 upward to a height of about fifty feet. Inspiration then followed, 

 and just before the animal left the surface close scrutiny could 

 detect a secondary puft' containing but little moisture, and rising 

 only to the height of a few feet. As to this second act of expira- 

 tion, a few words : I believe that in the cetaceans, respiration 

 being effected, the lungs in their function become hydrostatic. It 

 is obvious that to facilitate submarine progression the specific 

 gravity of the body must be equal to that of the surroundiu.'- 



