Meanings of vain conjectures in английском

He was left to vain conjectures, however, as to Roderick's actual moods and occupations.

We are, moreover, too superstitious in vain conjectures as to the future, that we derive from the words and actions of children.

Our bearings and our chronometer being at variance with the charts which we had to consult, we were lost in vain conjectures.

The purpose of this strange building, however, he kept secret; and his neighbours, after numerous vain conjectures, gave it the name of "Cooke's Folly."