Eddy Bentley writes
K wrote:
The milkiness is probably because it forms an emulsion, rather like
salad dressing. Oil on its own repels water, but if you mix it up
vigorously with water, the oil and water droplets get dispersed amongst
each other.

Thanks, Kay. So would that mean then that because Jeyes so easily forms
an emulsion that it's not going to be much good at repelling moisture
and wetness from exposed wood and I might as well forget using it near
wood for that reason?

No, not necessarily. As I said, oil and water can form an emulsion (as
in salad dressing) but oil on its own will repel water - eg if you oil a
cast iron frying pan you will protect it from rust.
--
Kay