Galileo's Instruments of Discovery
With these various instruments, Galileo Galilei was able to look into space and change our view of the universe.
- By Sarah Zielinski
- Smithsonian.com, July 20, 2009
This square could be used either vertically, as shown, or horizontally to measure heights and distances through triangulation. It also had a magnetic compass to determine direction. This square is from the 16th century.