The Epsilon Exordium

From the journal of Professor Caleb BlackThorne III, discovered May 1899, near the great Temple of Tiahuanaco, Peru:

[23 September: 1893]
Upon extensive examination of the nefarious arcane codex known as The Epsilon Exordium, i believe my search may at last be drawing to a close. Indeed, i feel that perhaps the great discovery which has eluded me for so long may finally be within my grasp. And yet I must be cautious, for twice more have i seen the figures in the night, watching me in silence from the confines of the darkness. I cannot discern their features, only that they are vaguely human in shape, save for their arms which seem abnormally long and oddly jointed. My native guides are becoming increasingly agitated and skittish, babbling incoherently about the guardians of the tombs... citing legends from their ancestral past which speak of mysterious travellers who reputedly came down from the stars in great silvern chariots drawn by steeds of flame.
At any rate, I have my trusted Martini-Henry .45 calibre breech-loader should these silent stalkers prove malign and ever deign to lay hold of me in the night. I have at last translated the carvings on the stone fragment i unearthed amidst the ruins of Angkor Wat. To my astonishment, I found that it predated the construction of the temple itself by countless thousands of years, and that it spoke of the same subject as did the hieroglyphs I beheld on the wall of the concealed chamber which I and Lord Blakiston discovered within the Great Pyramid in Egypt. Successive examinations of the edifices at Giza and Karnak revealed further parallels too precise to be mere coincidence. The
pieces of this great cosmic puzzle are finally beginning to fall into place...

[2 October: 1893]
Yes, it is as I suspected. I have long felt that the Sumerians of Mesapotamia were among the first peoples to attain elucidation concerning the dread matter i pursue. My excavations at Lagash, Eridu, and most notably the ziggurats at Ur, have revealed truths which subsequent finds at Angkor, Egypt and Sacsahuaman only serve to consolidate. I now know that the Olmechs, the Aztecs and the Mayans were also undeniably key tendrils of this grand global web, and the unnerving truth I hitherto felt compelled to deny now seems inexorably
to point to some grand and terrifying universal axiom.
It seems however, that the closer I come to enlightenment, the greater the danger becomes. Last night, one of our expedition's chief guides disappeared without trace. His native compatriots could find no tracks, nor offer any evidence of his departure to suggest that his superstitions had finally compelled him to abandon the party... the man seems simply to have vanished inexplicably into the oppressive, sweltering dark. In light of the disappearance, I opted not to inform the group that during the darkling hours before sunrise last night I had peered from my tent to behold what I perceived to be three of the shadowy figures I have previously described moving furtively in the gloom, keeping ever just out of the illuminatory radias of our campfire.
By the time I had brought my rifle to bear, they had melted away into the fathomless shadows of the benighted jungle...