Definition of "esoterics"

When indeed a Popish monarch may fill our throne, and the successor of St. Peter shall be the spiritual head of our Church; then shall your “esoterics,” alias “Church principles,” be in the ascendant in our Universities, and Who shall say that we may not have a Thorp lecturer in each of our Colleges, Neale and Webb scholarships, Regii professores supplying the places of those who shall now be superannuated, all teaching, and empowered to confer degrees in the, symbolism of mystical divinity:—the professor of music, not dealing as he now must, with crotchets and quavers, but in the far higher branches of the sacramentality of sounds, with their correspondent colours, instruments, bearing, &c. &c., and so of others?

1845, Clergymen of the Church of England, editors, The Christian’s Monthly Magazine and Church of England Review, volume IV, London: Simpkin, Marshall, & Co., pages 364–365