Using the balance shown here, the object would be placed in one pan and known masses would be placed in the other pan until the pans were exactly balanced.
(the pans; were; exactly balanced) (the balance; shown; L:here) (the object; would be placed; in one pan) (known masses; would be placed; in the other pan; T:until the pans were exactly balanced)
the pans the balance the object known masses
were shown would be placed would be placed
exactly balanced
L:here
in one pan
in the other pan T:until the pans were exactly balanced