Trains of reasoning aren't like advertisements.
You come to believe that a certain kind of pill will prevent your going bald because you've seen statements to that effect ten thousand times.
It's the cumulative weight of repeated assertion which compels belief in that case.

But the kind of belief which depends on reasoning is quite different.

If you've the sort of intellect which cannot grasp the proof which Euclid gives of one of his propositions, no number of repetitions of it will help you in the least.

That's a curious psychological law, but it is a law.

Therefore it would be the merest waste of time for me to demonstrate to you again that Mrs.Lorimer and Miss King are the same person.