68 "ALBATROSS" EASTERN TROPICAL PACIFIC EXPEDITION. 



ings close off the reef flat line of breakers — one off Tekava, at tlie most 

 one-third of a mile from the reef, in 225 fathoms. Our position, plotted by 

 tangents to the volcanic islands or by their summits, indicated in this case, 

 on the chart, a distance of one and one-half miles. A second sounding of 

 245 fathoms off the eastern horn at less than one-half mile, indicated on 

 chart No. 2024 a distance of two miles from the horn ; and a sounding of 

 241 fathoms one-fourth of a mile off the point which we had visited 

 (Vaiatekeue) indicated a distance of three-fourths of a mile on the chart. 

 The slope of the Gambler archipelago to the east is steep. On coming 

 in sisht of Manga Reva we sounded in 2070 fathoms at a distance of eleven 

 miles from Mount Duff, that is, six miles from the outer edge of the reef, 

 bearing southwest; and on coming out we sounded again half-way to 

 that point at a distance of three and one-fourth miles from the breakers 

 in 1394 fathoms. 



One cannot fail to be struck with the similarity of the Manga Reva 

 archipelago with the great atoll of Truk.' Darwin also called attention to 

 this from a study of the charts. Yet, owing to the great size of Truk, no 

 less than one hundred and twenty-five miles in circumference, and the great 

 distance of the barrier reef from the encircled volcanic islands, the effect as 

 one steams into Manga Reva is totally different from that produced by Truk. 

 In the latter some of the islands, though large, and of the same height 

 as those of Manga Reva, are much more scattered, and seem of compara- 

 tively small impin-tance in the midst of the huge lagoon which surrounds 

 them. The islets of the encircling reef of Truk are from eleven to fifteen 

 miles distant from the encircled volcanic islands. In Manga Reva, which is 

 only forty-five miles in circumference, after passing the small islands in the 

 southern and open part of the lagoon when once off Maka-pu, we can fairly 

 well take in the atoll as a whole (Pis. 14, 64-68). The westernmost island 

 (Tara-Vai) is only five miles off; Manga Reva and Au Kena are about 

 three, as are also the islets of the east face of the encircling reef ; these dis- 

 tances, as you approach the entrance to Rikitea, are constantly growing less, 

 so that when in the gap between Manga Reva Island and Au Kena, at the 

 foot of Mount Duff, none of the larger islands are more than three miles off ; 

 and the islets of the eastern face of the barrier reef are seen to the northeast 

 about four miles off. When on the summit of the central ridge of Manga 

 Reva one can, in a radius of a little more than four miles, take in the whole 



1 See Plate 11 (15. A. Chart lll'J) and compare it with 15. A. Chart f*S2 or Plate 231 Mem. M. C. Z. 

 Vol. xxxiii. 



