316 Voyage of C apt. Sir James C. Ross to the Antarctic. 



Sounding of the Ocean. — Capt. Ross, provided with a line of 

 3600 fathoms, or rather more than four miles long, on the 3d of 

 January, 1840 — in fine weather obtained soundings with 2425 

 fathoms of line, equivalent to a depression of 14,550 feet, (more 

 than 2f miles,) and very little short of the elevation of Mont 

 Blanc above the ocean. The line was capable of sustaining a 

 weight of seventy- four pounds, and was furnished with swivels 

 to prevent entanglement on its descent. The lat. was 27° 26' S., 

 long. 17° 20' W.j and only 45 miles N.W. of the place where 

 a shoal was marked on a chart as having been discovered 

 in 1701. 



St Helena, January 31, 1840. — An observatory was erected 

 near the late residence of Napoleon : but owing to the magnetic 

 influence of the volcanic rocks, no accurate results could be ob- 

 tained, either on land or on board the ships. This proved to be 

 a general fact with the volcanic islands which they visited. 

 I The line of least magnetic intensity was several times passed 

 by the ships in these regions, and by comparison with earlier ob- 

 servations, it appears to have moved northerly during the last fif- 

 teen years at the average rate of about thirteen miles per annum. 



February 22. — Soon after dark a number of cuttle fishes sprang 

 on board, fifteen or sixteen feet high over the weather-bow ; sev- 

 eral passed entirely across the ship, and fifty at least were found 

 on the deck. 



Waves. Feb. 29. — In a heavy swell the waves were twenty- 

 two feet high, eleven above and eleven below the ocean level; 



the velocity of the undulations was eighty-nine miles an hour 



and the intervals between the waves 1910'feet. 



Soundings.— March 3, lat. 33° 21' S., long. 9° E., soundings 

 were obtain i at 2677 fathoms — 16,062 feet, or dver three miles 

 and one-fourth. 



A c rent of cold water from the eastward passing round the 

 Cape of Good Hope along the African coast, has been long sus- 

 pected and its existence was now believed to be fully confirmed. 

 Its average breadth is about sixty miles, with a depth of two 

 hundred fathoms— the temperature at two hundred fathoms, 

 sixty miles from the land, being 43°*5, while that of the surface 

 ^ °. The atmosphere vapor, condensed into a cloud of mist, 



hangs over the stream. It extends only seven or eight miles 

 south of the Cape. 



March 17.— Cape of Good Hope.— -The Cape proved very fa- 

 vorable for magnetic observations, as sandstone is the basis ot 

 the country ; and every assistance was afforded by the British 

 official residents. 



April 11. — Soundings were obtained at one hundred and twen- 

 ty-five fathoms on the Aguiias Bank : but after sailing seven miles 

 on that course there were no soundings at three hundred and 



