Laptyev, started from the Lena in 1739, but encountered masses of drift ice in Chatanga bay, and with this ended the voyages to the westward of the Lena.
Laptyev sailed, but was stopped by the drift ice in August, and in 1739, during another trial, he reached the mouth of the Indigirka, where he wintered.
Korean harbours, except two or three which are closed by drift ice for some weeks in winter, are ice-free.
As to the seas, the formation of ice on the west and south coasts is rare, but in the central and northern parts of the Baltic drift-ice and a fringe of solid ice along the coast arrests navigation from the end of December to the beginning of April.
The south and west coasts are washed by the Gulf Stream, and the north coast by an Arctic current, which frequently brings with it a quantity of drift-ice, and thus exercises a considerable effect upon the climate of the island; sometimes it blocks the north coast in the summer months.
