 Complete the following phrase:  As a newspaper columnist, Prus commented on the achievements of scholars and scientists such as John Stuart Mill, Charles Darwin, Alexander Bain, Herbert Spencer and Henry Thomas Buckle; urged Poles to study science and technology and to develop industry and commerce; encouraged the establishment of charitable institutions to benefit the underprivileged; described the fiction and nonfiction works of fellow writers such as H.G. Wells; and extolled man-made and natural wonders such as the Wieliczka Salt Mine, an 1887 solar eclipse that he witnessed at Mława, planned building of the Eiffel Tower for the 