68 A NATURALIST ON THE "CHALLENGER." 



booby. The noddies (Anous stolidus and A. melanogcnys) are 

 small terns or sea swallows, black all over, with the exception of 

 a small white patch on the head. The booby (Sula leucogaster) 

 is a kind of gannet. The full-grown birds are white on the 

 belly, with a black head and throat ; the black ending on the 

 neck, where it joins the white in a straight conspicuous line. 

 The back is dark. The younger birds are brown all over. Some 

 few of both birds soon came off to have a look at the ship. 



We moved gradually up to the islands, sounding as we went ; 

 the Captain and Lieutenant Tizard mounted into the foretop, 

 and steered the vessel from thence, looking out for rocks. The 

 water is deep right up to the rocks, and a hawser was sent on 

 shore in a boat, and made fast round a projecting lump of rock, 

 and the ship was moored by means of it in about 100 fathoms of 

 water, although not more than 100 yards distant from shore. 

 Such an arrangement is only possible under the peculiar circum- 

 stances which occur here. The wind and current are constantly 

 in the same direction, and keep a ship fastened to the rock 

 always as far off from it as the rope will allow. 



I never properly realized the strength of an oceanic current 

 until I saw the equatorial current running past St. Paul's Eocks. 

 Ordinarily at sea the current of course does not make itself 

 visible in any way ; one merely has its existence brought to one's 

 notice by finding at mid-day, when the position of the ship is 

 made known, that the ship is 20 miles or so nearer or farther off 

 from port than dead reckoning had led one to suppose she would 

 be, and one is correspondingly elated or depressed. But St. Paul's 

 Eocks is a small fixed point in the midst of a great ocean 

 current, which is to be seen rushing past the rocks like a mill- 

 race, and a ship's boat is seen to be baffled in its attempts to 

 pull against the stream. 



Between the two extremities of the main body of rocks, is a 

 bay, enclosed by a somewhat semicircular arrangement of the 

 rock masses. We landed on the eastward side of this bay. 

 Landing from a boat is a little difficult. There is a perpetual 

 swell running in the bay, although it is on the sheltered side of 

 the rocks, and one has to jump as the boat rises, and cling to the 

 rocks as best one may. 



