National Geographic : 1892 Mar 21
The Maps of the Glacier. 55 at 200-foot intervals; it must be remembered that these pretend to no accuracy, but merely serve to show the general form of the surface, as well as I can indicate it by aid of memory and pho tographs. The altitudes above mean tide which were deter mined trigonometrically are given in black figures; those deter mined by barometer or estimated, in blue figures. Camp Muir was estimated to be 25 feet above mean tide. For the inlet I have made a separate map on a scale - , which shows well the position of the flags we used for measuring the motion of the glacier and the form and position of the ice front at various times. The contour lines here also are only very roughly approximate; the interval between them is 100 feet. The numbers give altitudes determined trigonometrically, ex cept those on the contour lines, which are estimated.
1892 May 15
1892 Feb 19