There is more the the story of Russell and the Pyramids than has been told.
Russell came up with his chronology before he became interested in the Great Pyramid, and attempted to use the Pyramid measurements to collaborate his chronology!
He obtained the necessary internal "measurements" he required from a diagram of the pyramid included in the book by Charles Piazzi Smyth!
Needless to say, the numbers obtained from such "measurements" were not accurate enough to be used in any prophetic calculations, so the source of these numbers was "obscured".
An attempt to indirectly "validate" the use of these numbers in Russell's book, Thy Kingdom Come was made by publishing within the book a kind letter written by Charles Smyth himself for the prepublication copy that was sent to him.
This was all an attempt to obscure the shaky foundation of the whole matter.
It was deliberately done, and shows that intellectual honesty was not a primary concern of Charles T. Russell.
Now if he didn't actually write the pyramid chapter in his book, that might make matters different, although as the listed author he still had the responsibility of maintaining the accuracy and integrity of the contents of the book.
Here is an interesting article about how the Pyramid's measurements actually were changed when the 1910 edition of the Thy Kingdom Come was published.
http://www.neirr.org/pyramidscheme.htm
It should be noted that Smyth's “endorsement” was still retained in the new edition, although the material he supposedly reviewed had been altered.
--VM44