The Society’s founder Charles Taze Russell, who had only several years of schooling but a great deal of business sense, at first affiliated himself with a group that expected the world to end in 1873.
While Charles Taze Russell was the principle founder of the Watch Tower Bible and Tract Society, that legal entity as he formed was not to hold "authority" over congregations. Russell did not believe in an authoritarian organization such the Jehovah's Witnesses. The JW doctrine of a "visible organization of God" on earth that is alleged to have sole authority to speak for God came about after Russell died. Russell did not believe in such a doctrines.
Russell probably had the equivalent of at least a Bachelor's degree before he formed the Watch Tower Society. He had been privately tutored in secular education as well having more than seven years of instruction from Bible students who had come before him.
I do not know any group that he affiliated himself with in 1873 other than the independent independent Bible study group in Pittsburgh, PA, but, at least from what Russell himself wrote it is highly unlikely that this group was expecting the "world to end in 1873." There were some of the Second Aventists who were claiming that the planet Earth would be destroyed by fire in 1873, but Russell himself certainly did not hold to such a view. His own words concerning that time were:
I was not a convert, either to the time [1873] he [Jonas Wendell] suggested nor to the events he predicted. I, in company with others in Pittsburgh, organized and maintained a bible class for the searching of the Scriptures, meeting every Sunday.
We reasoned that, if Christ’s coming were to end probation, and bring irrevocable ruin upon ninety-nine in a hundred of mankind; then it could scarcely be considered desirable, neither could we pray with proper spirit, “Come, Lord Jesus, Come quickly!” ( Revelation 22:20 ) We had rather request — much as we should “love his appearing” — that he remain away and our sufferings and trials continue so that “if by any means we might save some.” ( 2 Timothy 4:8 ; 1 Corinthians 9:22 ) Not only so, but great masses of scripture referring to the Millennial glory and teaching that “All nations which thou hast made shall come and worship before thee,” &c., &c., would be left unfulfilled if at His coming there should be a wreck of matter and a crush of world. — Psalm 22:27 ; 67:2 ; 72:11 ; 86:9 ; Isaiah 2:2 ; 25:7 .
We first saw Millennial glory — then the glorious work which is offered us as His Bride; that we are by faith the “seed of Abraham;” and as such, heirs of the promises, &c., in whom “all the families of the earth shall be blest.” (Galatians 3) This most certainly points to a probation in the future after He has come. Thus, speedily, steadily and surely God led us to recognize the second coming of our Lord as being not the sunset of all hope to mankind, but the “rising of the Sun of Righteousness with healing in his wings.” — Malachi 4:2
The Lord gave us many helps in the study of His word, among whom stood prominently, our dearly beloved and aged brother, George Storrs, who, both by word and pen, gave us much assistance; but we ever sought not to be followers of men, however good or wise, but “Followers of God, as dear children.” ( Ephesians 5:1 ) Thus growing in grace and knowledge for seven years, the year 1876 found us. — 2 Peter 3:18 . -- Supplment to the first issue of the Watch Tower, July 1, 1879.
Thus, in 1876, Russell had seven years of theological training behind him. However, 1876 was three years before Russell began publishing "The Watch Tower" in 1879, and it was eight years after 1876 when Zion's Watch Tower and Tract Society was legally incorporated.
However, it is important to note that, while Russell, before the year 1876, held great interest in the manner, purpose and effects of Christ's return, it was not until that year that Russell became interested in any date pertaining to that event. 1876 was two years after 1874, but it was in 1876 that Russell's attention was drawn to the work of N. H. Barbour, and the thought that Christ had returned invisible to human eyes in 1874. Russell had already concluded that Christ's return would not be in the flesh, for he had become thoroughly convinced that Jesus had sacrificed his flesh, and thus would return with a body of flesh, but rather with an invisible spiritual body. He was surprized to see that someone else had come to similar conclusions, and thus took an interest in what Barbour had to say about Christ's invisible return in 1874. Again, however, this was two years after 1874 had passed; Before 1873 and 1874 Russell never entertained any thought of Christ's return in either date.
Looking back on the time before Russell began to work with Barbour, Russell laments:
While he believed a bonfire to be the end of the world, and that probation ended with it, Bros. Geo. Storrs, Henry Dunn and others were preaching and writing of “the times of restitution of all things which God hath spoken by the mouth of all His holy Prophets.” ( Acts 3:21 ), and that “In the ages to come, God would show the exceeding riches of his grace.” ( Ephesians 2:7 ) Again, of what value would it be to know the time if we know nothing of the manner of Christ’s coming?
In other words, although Russell and others, before 1874, were interested in the "restitutrion" that was to follow Christ's return, Barbour had been preaching that the world (meaning the planet earth especially) would be destroyed by fire, and Barbour did not seem, at that time, to be interested in the restitution promises. In that sense, however, Russell did not even believe in the "end of the world" as that term generally meant at that time. Russell certainly never believe in any "doomsday," nor did he believe in an Armageddon such as the JWs teach. His view of Armageddon was that it was a period of time when the nations would be disciplined (not eternally destroyed) so that they may be prepared to accept the King Jesus.