A brief survey is made of the variations of the W. Greenland glaciers in post-glacial prehistoric and historic time. It is tentatively concluded that in post-glacial prehistoric time the variations were greater than in historic time, but varied in a uniform way parallel to the present ice margin. In historic time it appears that an advance commenced between 1500 and 1600, and an advance occurred in the 18th century. It is difficult to generalise about the maximum advances, there is a clear tendency for the maxima to occur before 1850 in the South, but in some other localities the maxima did not occur until 1900–1930.