I should add some additional material. Into 1875 Barbour taught that the Gentile Times would end in 1878. He and his associates had been disappointed in 1873 and 1874. They'd expected Christ to return and take them to heaven. When they adopted invisible presence views (prompted by Benjamin W. Keith) they separated two events they believed would be simultaneous: Christ's return and the heavenly glorification (they called it Translation). Barbour believed translation would occur in 1975. He and a small group awaited translation in Brockport NY in the spring of 1875. This failure destroyed most of his chronological frame work, and he sought solutions. He quickly found an alternative fulfillment for 1875 expectations, seeing it as the start date for restitution blessings and an invisible heavenly resurrection. He shifted to Elliott's calculation as the probable end of gentile times.
None of this research is original to me. This comes from Rachael de Vienne, PhD, one of the authors of the Nelson Barbour biography. I don't think this has been published anywhere yet. It's material destined for inclusion in a revision of their book. I am impatient for their second book which discusses Russell and his associates up to 1887. I've read some rough draft chapters. It's spectacular.