Ballot wheel

"Thou speculators on permanent motion, how many useless drawings in this search have thou created! Go together with the gold seekers"

In Leonardo's times the debate on the possibility to realize a permanent motion is rather common among scholars. Here is a device which consists of half wheels filled with weights that fall in alternation due to gravity. This study allows Leonardo to prove the impossibility for the human talent to create a device with a continuous motion.
Forster code II, sheet 91 r. 1490