“but the odd fact is that Copernicus had hit on the ellipse which is the form of all planetary orbits - had arrived at it for the wrong reasons and by faulty deduction - and having done so, promptly dropped it: the passage is crossed out in the manuscript, and is not contained in the printed edition of the Revolutions. The history of human thought is full of lucky hits and triumphant eurekas; it is rare to have on record one of the anti-climaxes, the missed opportunity which normally leaves no trace.”