March 19, 1886.J 



SCIEXCE. 



253 



storm : and not a single cast was missed, from 

 180° west to the Straits. 



The sounding-machine used was Sigsbee's im- 

 provement on Thomson's, and was mounted on 

 the starboard end of the bridge, which is just for- 

 ward of the smokestack. The soundings were 

 taken head to sea, the wind a little on star- 

 board bow ; the ship was easily kept in this posi- 

 tion by spanker, main topsail, and by working 

 the engines slowly. The seas were too heavy to 

 sound stern to wind, as was done by the Tuscarora 

 when she did such excellent work under Com- 

 mander Belknap. 



This line of soundings, running as it does very 

 close to the ice-limit, was chosen by the hydro- 

 graphic office with a view of completing for the 



gation. The energies of the hydrographic office 

 should be directed to clearing up the paths of 

 commerce by searching for reported dangers, and 

 this can only be done thoroughly by means of 

 deep-sea soundings. The scientific consideration 

 of the ocean-bed will naturally follow. 



Tins line of soundings of Commander Barker 

 would seem to show that the main bed of the 

 South Pacific eomniences just south of Chatham 

 Island, the depth increasing very rapidly for the 

 first 300 miles, until 3,002 fathoms is reached, in 

 longitude 170° west. Beyond this point the pro- 

 file shows no remarkable irregularities except in 

 longitude 150° west, where there is a depth of 

 2,915 fathoms, with 2,650 fathoms and 2,506 

 fathoms on each side. From longitude 135° west 



DEEP-SEA SOUNDINGS BY THE D. S. S. ENTERPRISE. 



From Wellington, New Zealand, across the South Pacific to the Straits of Magellan. 



present the deep-sea survey of the lower South 

 Pacific. 



In 18T5 the Challenger ran a line of soundings 

 in about 40° south latitude. Between this and 

 the line run by the Enterprise, the German ship 

 Gazelle, in 1875, also executed a series of sound- 

 ings, with somewhat greater intervals between 

 than those of the two lines already mentioned. 

 These three series give a fan idea of the general 

 depths in this part of the Pacific, and will prob- 

 ably be sufficient for all purposes for some time to 

 come. North of the Challenger's line, however, 

 over the entire Pacific, lines of soundings should 

 be rim in all directions, and at short distances 

 apart ; and the hydrographic office has laid out a 

 plan by means of which this can be done from 

 time to time, by our war ships, most economically 

 and effectively, to accomplish the practical result 

 of determining the existence of dangers to navi- 



the depths decrease quite regularly until 118° 

 west is reached, where the least depth. 1.562 fath- 

 oms, was found. Beyond this the depths increase 

 again quite regularly to the base of the continent. 



This rise in the ocean-bed would point to the 

 possible existence of a ridge running generally 

 north and south, and limited, as far as known, by 

 Easter Island, in latitude 27° 09' south, longitude 

 109° 25' west, and Dougherty or Keates Island in 

 latitude 59 : 21' south, and longitude 119° 07' west. 

 This ridge is also indicated by a sounding of 1,600 

 fathoms, taken by the Challenger in latitude 38° 

 43' south, longitude 112° 31' west. 



The lines of soundings taken by the Challenger 

 and the Gazelle from 100° to 150° west run gen- 

 erally parallel to that of the Enterpiise, and show 

 a remarkable uniformity in the depths along the 

 same meridian in the belt of the South Pacific, 

 between latitude 40° and 50° south. 



