电流概念的形成是电学理论发展中最重要的步骤。

Never stop learning, because the land and the livestock will always teach you something new.《The Future of Farming》

释义：船装载过重就会沉没，人欲望太强就会损害生命。劝诫人要节制自己的欲望。

The first fruit of this imagination - and the first lesson of the social science that embodies it - is the idea that the individual can understand his own experience and gauge his own fate only by locating himself within his period, that he can know his own chances in life only by becoming aware of those of all individuals in his circumstances.