Lavinia didn’t actually have to throw Emily into a trance; controlling her dreams was sufficient!
Emily Fisher has been emotionally conditioned to submit to her ancestress, Lavinia Priest. Bad enough that Lavinia’s been dead over a century. Worse that she was, in Alex Bancroft’s words, “barking mad.” But what does she want? And how can Emily help her? Find out in “Serving Lavinia,” chapter 31 of Prophecies and Penalties, my serial about a murder investigation on a Vermont religious commune. If you’re not already reading this story, you can begin at the beginning.
The image, by the way, is originally from the 1891 volume of Cassell’s Family Magazine Illustrated, a British periodical, for a story called “Tracked: A Mystery of the Sea,” by the Rev. C. N. Barham, illustrated by W. H. Margetson. The story, which purports to be true, explains the fate of a missing ship by using clairvoyance. In typical nineteenth-century fashion, a superior male, the minister-narrator, hypnotizes an inferior female, a servant, to use her clairvoyance to solve the mystery.
Of the Rev. Barham I have been able to learn very little, not even his vital statistics. He was British, presumably a divine in the Anglican Church. He must have traveled to India as a missionary at one time, and retained an interest in propagating the gospel abroad. He later lived in Kent, where circa 1836 he married the daughter of a British esquire who lived in Calcutta. He apparently wrote religious songs in the 1860s, and was contributing to British literary magazines in the 1890s. Several websites confuse him with Richard Harris Barham, who was also a divine and who wrote The Ingoldsby Legends.
W. H. Margetson turns out to be William Henry Margetson (1861 – 1940), best known for painting pictures featuring beautiful women. He must have supplemented his earning as a painter by doing magazine work. I looked at quite a few images of his painting, and I must say he does indeed do a good job with beautiful women. Here are two examples:
“At the Cottage Door” by William Henry Margetson
“Poseidon’s Mistress on the Shore” by William Henry Margetson
Sillyverse 
From this small selection of paintings, I would say William Henry Margetson had a particular liking for coquettish young ladies. Was he a reverend, too?
Not EVERY woman he painted was coquettish and young, and a few were a bit more than coquettish, to judge from his “Cleopatra.” While one does wonder if he’s another rakish reverend, so far as I know he was not.