人口論
Louisa and Thomas, two of Mr. Gradgrind's children, go after school to see the touring circus run by Mr. Sleary, only to meet their father, who orders them home. Mr. Gradgrind has three younger children: Adam Smith (after the famous theorist of laissez-faire policy), Malthus (after Rev. Thomas Malthus, who wrote "An Essay on the Principle of Population", warning of the dangers of future overpopulation), and Jane.