FOR THE SOUTH LAND 
43 
struct the first map of magnetic variation, and as another 
he introduced a method of determining longitude by ob- 
serving occultations of the fixed stars. These were two 
substantial gains to navigation, for hitherto the problem 
of the longitude had been practically insoluble. 
The solitary scientific expedition toward the south was 
merely an incident without any direct consequences to 
exploration. The mercantile or piratical adventurers 
of England continued to visit the southern seas and 
several times were driven south of 6o°. Dampier in his 
famous circumnavigation, although attaining no high 
latitudes, helped to cast doubt upon the existence of a 
great southern continent by observing how frequently 
the coast-line marked on the charts was found to have 
no basis in fact. One of his comrades, however, John 
Welbe by name, was convinced of the existence of such 
a land, at least he addressed many memorials in 1713 
to the Admiralty and the Treasury asking for a ship 
with 180 men in which he could explore the coast of the 
continent between Cape Horn, the Land of Juan Fer- 
nandez and New Guinea ; but the Admiralty and Treasury 
had other things to think about and remained silent. 
It would serve no purpose to recall the names of all the 
sailers of this period who were driven south of 6o° 
while rounding the Horn, but George Shelvocke may 
be mentioned because his particular storm in 1719 was 
imputed by his superstitious mate to the presence of a 
“ disconsolate black albitross ” which followed the ship, 
and after several vain attempts the mate shot the bird. 
It did not die in vain, for the report of the episode 
suggested to Coleridge the poem of the Ancient Mariner. 
In 1721 Jacob Roggeveen submitted a scheme for a 
voyage of southern exploration to the Dutch East India 
