science

Chart with characters in the Roman alphabet (for English, German, and other European readers), Japanese, Chinese, Russian, and Hebrew. A panel in the center replaces the alphabetic characters with symbols for children and adults who were illiterate or who could not read

Beautiful multilingual eye examination chart of the early 1900s San Francisco

7 March 2019 7 March 2019

112 years ago, optometry was a growing profession. In diverse cities like San Francisco, however, the eye chart commonplace in western countries today could not suffice.

Home on Lagrange

6 November 2014 22 February 2019

I first came across Lagrangian Points many years ago in Arthur C. Clarke’s novel A Fall of Moondust. It boggled my young mind, picturing satellites orbiting in seemingly static positions around the Moon!