The mesolabium of Eratosthenes to find cube roots. (This will find cube roots of numbers between 0 and 1.)

Move point *D* up and down using the mouse until the length of *DI* is the desired value. Then use the mouse to move triangle *QSH* back and forth and triangle *UTI* back and forth until points *A*, *B*, *C*, and *D* are all on the same line. Then the length of *BG* will be the cube root of the length of *DI*.

(This is based on pp.184-185 of David Burton, *The History of Mathematics: An Introduction, Seventh Edition*, 2011, McGraw-Hill.)