It doesn't indicate that 1914 would be a year identified for some sort of apocalypse that would annihilate the wicked. It states that 1914 would usher in the onset of the signs described in Matthew 24:7, 8. It's official beginning in 1874 is clearly explained in Thy Kingdom Come.
The Harp Of God.
 When the gentile dominion legally ends, the order being a wicked one under the supervision of Satan, the god of the evil world (2 Corinthians 4:3,4), and all these nations lying in the wicked one (1 John 5:19), it would be expected that the gentile kingdoms and nations would strive to hold on to their power. But when the proper time should come it would also be expected that the Lord, whose right it is, would take over the affairs into his own hands. And so he said: "We give thanks, O Lord God Almighty, which art, and wast, and art to come; because thou hast taken to thee thy great power, and hast reigned. And the nations were angry, and thy wrath is come, and the time of the dead, that they should be judged, and that thou shouldest give reward unto thy servants the prophets, and to the saints, and them that fear thy name, small and great; and shouldest destroy them which destroy the earth."—Revelation 11:17,18.
 It will be observed that the Lord does not do all of his work in a twenty-four-hour day, but that gradually he performs his sovereign will. Specifically answering the question concerning the end of the world during the time of his presence, Jesus said: "Nation shall rise against nation, and kingdom against kingdom; and there shall be famines, and pestilences, and earthquakes [literal and symbolic—revolutions] in divers places. All these are the beginning of sorrows." (Matthew 24:7,8) Exactly on time, at the end of the gentile dominion, at the beginning of the end of the world, nation rose against nation and kingdom against kingdom in the most devastating war that man ever dreamed would come to the world. There followed in its wake a great pestilence, the Spanish influenza, which swept the earth; and the famine is still raging amongst many peoples and kindreds of the earth; and there have been revolutions, as well as many literal earthquakes in various parts of the earth. And these, said the Master, mark the beginning of the end of the world, which takes place during the time of his presence. The evidence here is overwhelming, proclaiming his presence and the end of the world.
They clearly stated the same thing here in 1891. The era prior to 1914 was characterized by an increasing of knowledge (preparation for the last days) and had its official beginning in 1799 which makes perfect sense according to their calculations. 1914 would culminate into a time of great trouble.
1891 Thy Kingdom Come 1st Ed.
This Time of the End, or day of Jehovah preparation beginning A. D. 1799 and closing A. D. 1914, though characterized by a great increase of knowledge over all past ages, is to culminate in the greatest time of trouble the world has ever known; but it is nevertheless preparing for and leading into that blessed time so long promised, when the true Kingdom of God, under the control of the true Christ, will fully establish an order of government the very reverse of that of Antichrist. Page 59
The typical Jubilee cycles pointed out A. D. 1874 as the date of our Lord's return; and yet the date was therein so ingeniously hidden, as to make its discovery impossible until the "Time of the End." And this testimony was made doubly strong by proofs from two standpoints-the Law and the Prophet-the two being entirely independent of each other, and yet equally clear and convincing. Page 125
All of this makes perfect sense to me. I don't observe that the future refinement of 1914 as the official date of Christ's second advent is anything to criticize or that what was stated in the Harp of God conflicts with future publications.