what "Ministry of Angels" refers to in volume I of The History of Spiritualism by Arthur Conan Doyle?
Judge Edmonds was pointed at in the streets as a crazy Spiritualist. Wealthy merchants were compelled to assert their claims to be considered sane and maintain their commercial rights by the most firm and determined action. Professional men and tradesmen were reduced to the limits of ruin, and a relentless persecution, originated by the Press and maintained by the pulpit, directed the full flow of its evil tides against the cause and its representatives. Many of the houses where circles were being held were disturbed by crowds who would gather together after nightfall and with yells, cries, whistles and occasional breaking of windows try to molest the quiet investigators in their unholy work of "waking the dead," as one of the papers piously denominated the act of seeking for the "Ministry of Angels."