Surely there must be some deficiency in an instrument that can play such havoc with the human soul. There is. The general who advised his troops to hold their fire until they saw the whites of the enemy's eyes knew the value of the human eye as a subsidiary weapon. That is the real reason why a row over the telephone is so shattering. You can't see the whites of your adversary's eyes or his teeth; you can only hear the latter snapping. You can both shout until piebald in the face, but where's the satisfaction of shouting a face piebald if you can't see it going piebald? You can call each other all the superlative twirts and lying hounds known to unnatural history, but you both hang up feeling that a strand of copper is a poor substitute for a block of wood.