Dr Brewer explains this as follows: ‘You cannot do two opposite things at one and the same time; you cannot exhaust your energies in one direction, and yet reserve them unimpaired for something else. If you go to bed late you cannot get up early.’
‘I’ve got to get this ironing done,’ said Mrs Mills.
‘But it’s after midnight,’ protested her husband. ‘Far better come to bed, and do the ironing in the morning. Burning the candle at both ends isn’t good for you.’