Just a knack.

I'll teach you if you like." "Will you?
That's splendid." "You are the strongest swimmer, Miss Graham, for a girl, that I ever saw.

You must have practiced a great deal." "Yes, Horace--my brother--taught me.

He is a splendid swimmer, one of the very best." "Horace Graham?
Why, you don't mean Horace Graham of the Harvard Athletic ?" "Yes, I do.

He is my brother.