Elements of Mind — Walter H. Hunt

In this Victorian historical fantasy, an English mesmerist goes on a quest for an idol that has the power to destroy humanity.

In Victorian India, a Scottish doctor, Dr. James Esdaile, finds a way to use the power of mesmerism to aid him in performing surgeries, using a remarkable artifact that enhances his abilities. The revocation of his promise to bring the artifact to Rev. William Davey, the head of the secret Committee of English mesmerists leads Dr. Esdaile to commit suicide in the center of the Crystal Palace . . . but that is only the beginning of the story. Davey's pursuit of the object leads him across two continents, unfolding the story that has its origins two decades before -- and reveals the secret world of the chthonoi, the elemental spirits that were banished from human lands in antiquity, and now want to find a way to open the Glass Door and reassert themselves in the world of men.
“Walter Hunt always keeps you reading and makes you think.” �"Harry Turtledove, New York Times�"bestselling author of Three Miles Down