Gas is indispensable in the operation of dirigible balloons, and gas is expensive.
It would seem that for the first of these duties they are indispensable.
To effect this object, an alteration of the French frontier is indispensable.
An equipage, indeed, is the one indispensable luxury of Rome.
There are all sorts of indispensable formalities to be observed.
You are aware that in these sort of transactions ready money is indispensable?
There he found what is indispensable to such a man—congeniality.
I shall take care to explain all those which appear to me indispensable.
Rivalry is an indispensable and normal adjunct of such unity.
And of these, the following, if not the most piquant and interesting, are the most indispensable to our History.