CHARLES WILKES 
215 
departure from Norfolk, and shape your course to Rio 
Janeiro, . . . determine the longitude of that place, 
as well as of Cape Frio; after which you will either de- 
tach a vessel or proceed with your whole squadron, to 
make a particular examination of Rio Negro. . . . 
Having completed this survey, you will proceed to a 
safe port or ports in Terra del Fuego, where the mem- 
bers of the Scientific Corps may have favorable oppor- 
tunities of prosecuting their researches. Leaving the 
larger vessels securely moored and the officers and 
crews occupied in their respective duties, you will proceed 
with the brig Porpoise, and the tenders, to explore the 
Southern Antarctic, to the southward of Powell’s Group, 
and between it and Sandwich Land, following the track 
of Weddell as closely as practicable, and endeavoring to 
reach a high southern latitude ; taking care, however, not 
to be obliged to pass the winter there, and to rejoin the 
other vessels between the middle of February and be- 
ginning of March. The attention of the officers left at 
Terra del Fuego, will, in the meantime, be specially 
directed to making such accurate and particular exam- 
inations and surveys of the bays, ports, inlets, and 
sounds in that region as may verify or extend those of 
Captain King. . . . 
“ You will then on rejoining the vessels at Terra del 
Fuego, with all your squadron, stretch towards the 
southward and westward as far as the Ne Plus Ultra 
of Cook, or longitude 105° W., and return northward to 
Valparaiso. . . . Proceeding once more from that 
port, you will direct your course to the Navigator’s 
Group, keeping to the southward of the place of depart- 
ure, in order to verify, if possible, the existence of cer- 
tain islands and shoals, laid down in the charts as doubt- 
