On Tuesday, March 20, 2018, A. P. Garcia <a.phillip.garcia@gmail.com> wrote:

On Mar 20, 2018 2:58 PM, "Tim Bradshaw" <tfb@tfeb.org> wrote:
This seems like an unduly complicated theory.  Maxwell had a good 19th-century Scottish gentleman's education (he knew great chunks of Paradise Lost by heart as a child) and he would have been far more familiar with classical literature than most scientists are today as a result.  Chances are he knew what daemons were in mythology because he'd  read either the Greek originals or Latin translations at school & university.

Given that, he could also have read about them in Plato's Republic when he discusses the myth of Er at the end of the work. 

Exactly.  Plato also writes extensively on it in his other works, e.g. Cratylus.  He is using the term 'daimones' and it could be best described as the guardian angel of the Christians.  So there is a big difference between evil demons (devils) of Christianity and the daimon of Socrates and Plato.