1
There is, of course, no infallible touchstone by which we can tell offhand.
2
Fortunately we have each of us an infallible touchstone by which we can judge of our love of truth.
3
No whit disheartened, she turns from one sect to another, trying each by the infallible touchstone of that clear, child-like conscience.
4
We shall probably not arrive at any definition which can be applied as an infallible touchstone to distinguish the dramatic from the undramatic.