Charled Macartney (Australian skipper and great batsman) maintains that at Leeds in July 1909, Barnes bowled the legendry Victor Trunper .....'with a sort of ball that a batsman sees only when he is tight (drunk). I was at the other end, I should know !'
More on what he bowled ...
It is ...at any rate clear that Barnes executed his leg break without turning the wrist, an action which gives some notice to the batsman. Appartently Barnes manipulated the leg turn mainly by leverage of the third finger - as most leg spinners do, though most of them need to twist over the wrist."
This probably explains his maintaing the seam position as would an inswing bowler so that the ball would swing inwards in the air and still break away on pitching.
....Mentally mingle the best of Tate and Bedser; length, pace, swing, then add a tincture of Orielly, then maybe some adumbration will emerge or loom of Barnes in full spate.