I think they make the common error of ascribing the 4 condensed modern equations to the list of 20 he came up with at the time. I also really enjoyed the insight he spent some time summarizing and investigating the work of Faraday and Cavendish. I am a little afronted by the claim that he proved lines of force when he concluded they were feeble junk science MP4 recording     MP3 recording -- -- Your browser does not support the audio element.