Click to open image viewer. George Willis Ritchey built this mirror grinding machine at the Yerkes Observatory in Williams Bay, Wisconsin, in the late 1890s. Under the sponsorship of George Ellery ...
Click to open image viewer. This is the electric motor that replaced the original overhead belt-driven drive on the mirror-grinding machine built by George Willis Ritchey at the Yerkes Observatory in ...
Some results have been hidden because they may be inaccessible to you
Show inaccessible results