What does he mean by "Line"?

Question

Six months at sea! Yes, reader, as I live, six months out of

sight of land; cruising after the sperm-whale beneath the

scorching sun of the Line, and tossed on the billows of the

wide-rolling Pacific--the sky above, the sea around, and nothing

else!

Answer 1

The Line Islands are a group of little islands and atolls that run roughly along the equator in the central Pacific. They are frequently used as a nautical point of reference.