An auditor is checking the books of an airline. He is puzzled by the excess use of fuel on a Melbourne to Canberra flight. He rings up the pilot and asks for an explanation. ""It was late at night'"" says the pilot ""Canberra was covered in fog and I lost my bearings."" ""I'm sorry"" says the auditor ""but you'll have to bear the cost yourself."" ""The cost of what?"" asks the pilot. ""Of the bearings you lost.""