Moreover, when the questioning takes on a sarcastic or ironic tone as it is apt to do, or when it takes on a hostile note as is sometimes almost inevitable, the danger is 15 not only that witnesses will be unable to present the evidence they may wish, but the parties may begin to think, quite wrongly it may be, that the judge is not holding the scales of justice quite eventually"(1) In Jones vs National Coal Board Lord Justice Denning observed: "The Judge 's part in all this is to hearken to the evidence, only himself asking questions of witnesses when it is necessary to clear up any point that has been over looked or left obscure; to see that the advocates behave themselves seemly and keep to the rules laid down by law; to exclude irrelevancies and discourage repetition; to make sure by wise intervention that he follows the points that the advocates are making and can assess their worth; and at the end to make up his mind where the truth lies.