xxv j INSTRUCTIONS. 
At Rio Janeiro, where you will replenish your supplies, taking 
special care to furnish yourself with a sufficiency of all those articles 
which are considered the best preventives and remedies for the 
scurvy. You will determine the longitude of that place, as well as of 
Cape Frio ; after which, you will either detach a vessel, or proceed 
with your whole squadron, to make a particular examination of Rio 
Negro, which falls into the South Atlantic about latitude 41° S., with 
a view to ascertain its resources and facilities for trade. 
Having completed this survey, you will proceed to a safe port or 
ports in Terra del Fuego, where the members of the scientific corps 
may have favourable opportunities 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 endea- 
vouring 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 beginning of March. The 
attention of the officers left at Terra del Fuego, will, in the mean time, 
be specially directed to making such accurate and particular exami- 
nation and surveys of the bays, ports, inlets, and sounds, in that 
region, as may verify or extend those of Captain King, and be ser- 
viceable in future to vessels engaged in the whale-fisheries, in their 
outward and homeward-bound passages. 
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 north- 
ward to Valparaiso, where a store-ship will meet you in the month of 
March, 1839. Proceeding once more from that port, you will direct 
your course to the Navigator's Group, keeping to the southward of 
the place of departure, in order to verify, if possible, the existence of 
certain islands and shoals, laid down in the charts as doubtful, and if 
they exist, to determine their precise position, as well as that of all 
others which may be discovered in this unfrequented track. When 
you arrive in those latitudes where discoveries may be reasonably 
anticipated, you will so dispose your vessels as that they shall sweep 
the broadest expanse of the ocean that may be practicable, without 
danger of parting company, laying-to at night in order to avoid the 
chance of passing any small island or shoal without detection. 
