In Thomas Hardy's short story "The Withered Arm" (freely available to read online), Gertrude Lodge and Rhona Brook go together to see a man named Trendle, often called Conjuror Trendle, who is reputed to have some knowledge or ability with magic. He's the one who tells Gertrude that her affliction comes from Rhona, and also the one who tells her a possible way to get rid of it. After Gertrude's second, lonely, visit to him, we have the following paragraph from the start of Chapter VII:
The communication sank deep into Gertrude's mind. Her nature was rather a timid one; and probably of all remedies that the white wizard could have suggested there was not one which would have filled her with so much aversion as this, not to speak of the immense obstacles in the way of its adoption.
Why is he referred to as a "white wizard"? It surely doesn't mean his complexion, since he's described at their first meeting with him as "a grey-bearded man, with a reddish face". Was the phrase "white wizard" used in rural England at those times to denote a "conjuror" such as him? I've tried searching the internet, but of course nowadays most references to "white wizards" are from fantasy and the search results are full of those.