Which preposition to use with determinable

by Occurrences 4%

Q.You have now shown that the performance of an engine is determinable by the indicator; but how do you determine the power of the boiler? A.By the quantity of water it evaporates.

on Occurrences 1%

In wagon and tubular boilers very different proportions prevail, yet the proportions of every kind of boiler are determinable on the same general principle.

Which preposition to use with  determinable