From Jehovah's Witnesses: Proclaimers of God's Kingdom, pp. 133-134:
of the Gentile TimesEnd
The matter of Bible chronology had long been of great interest to Bible students. Commentators had set out a variety of views on Jesus’ prophecy about "the times of the Gentiles" and the prophet Daniel’s record of Nebuchadnezzar’s dream regarding the tree stump that was banded for "seven times."—Luke 21:24, KJ; Dan. 4:10-17.
As early as 1823, John A. Brown, whose work was published in London, England, calculated the"seven times" of Daniel chapter 4 to be 2,520 years in length. But he did not clearly discern the date with which the prophetic time period began or when it would end. He did, however, connect these "seven times" with the Gentile Times of Luke21:24.
True, John Aquila Brown published the book The Even-Tide in 1823 in which he taught that the Gentile Times was a period of 2,520 years that went from 604 BC to 1917 AD. However, for Brown, the end of the Gentile Times meant the "transcendant 'glory of Israel'" and was related to the natural Jewish nation (see title page).
The chapter on the 2,520 years from Brown's book The Even-Tide (about 2 MB) can be downloaded from this file sharing site:
http://www.filesend.net/download.php?f=e91866a43723c510c1c874de52217f34
Edited to put correct URL for download