Well, remember too, that according to Russell, October 1874 marked the start of the antitypical Jubilee, the end of six millenniums of sin among mankind. Fred Franz, in the '40s, with his "reliable Bible chronology" and realizing the error of 100 years in the KJV changed the end of such six milleniums to 1975 (plus however long [edit] it took to create Eve). Notice:
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jv chap. 28 pp. 631-632 Testing and Sifting From Within ***Something else that was seen as a possible time indicator involved the arrangement that God instituted in ancient Israel for a Jubilee, a year of release, every 50th year. This came after a series of seven 7-year periods, each of which ended with a sabbath year. During the Jubilee year, Hebrew slaves were freed and hereditary land possessions that had been sold were restored. (Lev. 25:8-10) Calculations based on this cycle of years led to the conclusion that perhaps a greater Jubilee for all the earth had begun in the autumn of 1874, that evidently the Lord had returned in that year and was invisibly present, and that "the times of restitution of all things" had arrived.—Acts 3:19-21, KJ.
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ka chap. 11 pp. 209-210 "Here Is the Bridegroom!" ***In the year 1943 the Watch Tower Bible and Tract Society published the book "The Truth Shall Make You Free." In its chapter 11, entitled "The Count of Time," it did away with the insertion of 100 years into the period of the Judges and went according to the oldest and most authentic reading of Acts 13:20, and accepted the spelled-out numbers of the Hebrew Scriptures. This moved forward the end of six thousand years of man’s existence into the decade of the 1970’s. Naturally this did away with the year 1874 C.E. as the date of return of the Lord Jesus Christ and the beginning of his invisible presence or parousia.