This drawing of Mare Crisium (Sea of Crises) was based on a negative taken at the Lick Observatory August 23, 1888. Weinek began with a faint positive enlargement on special paper, and then spent 35 hours highlighting with watercolors. The resulting drawing contains slightly more detail than the direct positive print, and is much more pleasing to the eye. Weinek's artwork may be compared with Tobias Mayer's drawing of a century earlier (see item 25).