INTRODUCTORY CHAPTER. 
17 
which bounds the northernmost point of the continent 
in 72° N. Owing to the long absence of this expedi¬ 
tion, Captain Back, supported by public subscription, 
was sent in search of it. He wintered in 1833 on Great 
Slave Lake, and in 1834 descended the Back Biver to 
its mouth, and explored the coast from Cape Britannia 
to Point Richardson, thus almost reaching the southern 
termination of James C. Rosss sledge journey. Back’s 
voyage, in 1836, failed in accomplishing its object, but 
the work which it was proposed to do was in great part 
effected in the years 1837, 1838, and 1839, by Messrs. 
Dease and Simpson, who, in a series of boat-voyages, 
traced the coast from Point Barrow to the estuary of 
the Back River. The/ laid down portions of Wol¬ 
laston Land, and of King William’s Island. Thus, the 
only gap in the completion of the North-West Passage 
was a connection between Franklin’s Channel and the 
Gulf of Boothia. Dr. Rae was selected to make this 
completion. He surveyed portions of the Gulf of 
Boothia, and found that the Boothia isthmus separated 
this gulf from the sea explored by Dease and Simpson. 
In 1845 Sir John Franklin was sent out in command 
of the Erebus and Terror to attempt the North-West 
Passage. In July the expedition reached Whale Fish 
Island, Baffin’s Bay, from whence letters were- 
despatched, and the last that was seen of it was; 
