WT Dec 1880 (No. 6) p. 5 "False Christs"
"We have reason for believing that after 1881, there will be wonderful spiritual manifestations. The prince of the power of the air...[Devil and his angels]--The rulers of the darkness of this world [wicked spirits--] will now make a last great effort previous to their binding, at which time these powers will be subdued.
Those angels which kept not their first estate God hath reserved in everlasting chains under darkness unto the judgment of the great day. They were cast down to hell. ("Tartarus" lower atmosphere--our air.) For 6000 years these spiritual powers have been deceiving and misleading mankind.
These like the good angels, have also had power to appear as men, but they must always appear in the dark, for God had placed them under darkness."