I was ashamed when I caught myself in such digressions or when called to task by a companion as I had noted the seemingly eternal vigilance of the Professor; who always, whether he happened to be assisting with the trolley, which Van Damm and Holden were pushing this afternoon, or checking the compass, had a free hand for his naked revolver which he carried with a lanyard looped round his wrist at all times.
The throbbing noise which we had heard earlier and which had apparently ceased, now began again; but only in snatches, due to a change in the wind? But that could not be so as a compass check by Van Damm revealed that, as always, what wind there was blew lightly but fairly steadily from the north. The sound was like the faintest heartbeat, apparently from many miles away, but accompanied by emanations or vibrations which appeared to pulsate the very rock across which we walked. The party stopped for nearly an hour at one point while Scarsdale and Van Damm made certain instrument tests, but nothing specific could be ascertained from these.
Soon after we commenced walking once more the mist oegan to thin and we began a fairly steep climb uphill. This was so unusual that the exact time, together with latitude and longitude was noted by Scarsdale and Van Damm and more instrument bearings were taken. So far as we could see the slope up which we walked was man-made and this was exciting in itself; traces of the extremely hard and sophisticated tools which had sliced the roadway from the steel-hard rock were noted by my companions with wondering exclamations.
Van Damm and Holden were still hauling the trolley, this time with the aid of the special harness straps Scarsdale had developed, but the slope was not of sustained steepness, levelling off to a more tolerable angle shortly afterwards, so that both men declined the help of Prescott and myself. At one stage I found myself leading the party, though Scarsdale was not far behind, swinging his revolver in his usual vigilant fashion. Before me in the dim light began to range a series of oblong boxes and my excited remarks soon brought the rest of the party up.
We now advanced along a broad highway, past a slabbed obelisk bearing more of the strange inscriptions which we had already observed. Scarsdale quickened his steps, barely pausing to note the inscriptions, in itself a matter of wonder as he and Van Damm had taken up many hours in the past few days in such examinations. The trolley party was hard put to it to keep up as we three unencumbered members pushed on rapidly as the strange rectangles and cubes grew before us in the twilight.
What we were entering was a town or city of vast and unknown size, many miles beneath the surface of the earth and whose use and purposes were obscure to us. As we advanced further along the broad highway the blocks began to tower before us until I realised that the scale upon which the town was built was as vast as anything we had yet encountered. The blocks were windowless and without any break in their smooth grey outlines except for the vast portals of dressed stone, similar to those we had already noted.
Some had smoothly traced lintels upon which were graven strange and baffling hieroglyphs, whose very outlines looked obscene and depraved; the highway along which we walked presently gave upon a vast square, around which the gigantic buildings were grouped in no identifiable order or in no observable pattern. The whole rhythmic structure of the city was complex and puzzling to a stranger and I had trouble with the angles and vistas, some of which, as we passed what would be called alleys and road junctions on the earth above, caused serious optical illusions for the members of our party.
The square, hewn of what appeared to be enormous blocks of stone, also seemed to run away at disturbing angles, with none of the blocks ever quite seeming to join at the proper juncture; instead of the paving thus formed being square or triangular it seemed to obey no observable law or mathematical formulae so that the eye was always being shocked by strange breaks in the formation or ugly or jarring groupings of lines. This was one of the most difficult aspects of the place and one which we were never able to overcome.
For as one advanced towards a given spot the natural law seemed to be restored; all angles met in the correct fashion, square joined to square and curve to curve. But once we had turned about or walked away from a measured point the optical illusions began again so that one began to fear for one's sanity. It was a fascinating and troubling place and one to provide endless discussion between our scientific members. Neither was my photographic work able to resolve the problem for all the studies which survived the expedition yielded nothing but the normal, however long one stared at enlargements of the prints.
We put down our equipment in the middle of the gigantic plaza and rested, sitting on an elaborately sculptured piece of stone; made from one solid slab of black material, it was elaborately incised not only with hieroglyphs but with intricately chased surfaces which broke up its outline and presented a baffling, many-surfaced structure to the viewer. Nowhere on the floor of the plaza could we detect any scratches or markings which might have been caused by the passage of vehicles in the long-distant past.
The Professor was once more consulting his typed notes and his much thumbed transcription of The Ethics of Ygor.
'As you have no doubt observed, Van Damm,' he said with a faint smile of triumph, 'we are now within the ancient city of Croth.'
'Indeed, Professor,' observed Van Damm with a thin smile in return. 'Here is your vindication.'
And he indicated the broad spread of the city with an expressive gesture of his lean arm.
We were not long idle. Scarsdale rapidly designated the area as Camp Five and, as always on the Great Northern Expedition, we first set to erecting the tents, sorting stores testing equipment and preparing our late afternoon meal.
Only then, when we had mounted the first sentry and set up the ugly snout of the inevitable machine-gun commanding the broad spaces of the square, did Scarsdale feel that we were at liberty to explore.
He chose for this first excursion the most massive and curious of the buildings surrounding the square; here again, there were difficulties in gaining the entrance. There was a long series of elaborately engineered ramps and ledges which we had first to surmount and then a short but exhausting flight of steps into the interior. We gained a sort of terrace at the top and turned to look back at Camp Five; the distortion of perspective there, some ten metres above the level of the square, was startling and our tents and stores appeared suspended on a heap of tumbled paving blocks.
Prescott had been left behind and on some members of our party waving, he saluted in reply; it was extraordinary to see what a fragmentary gesture it appeared, with his arm appearing completely disconected from his body. I had some fears under these weird optical conditions, even if we did meet a prospective target, and I voiced them on this occasion to Scarsdale. He said nothing but his eyes looked troubled.
We paused awhile on this balcony, taking in the bizarre and jumbled vista of Croth, its buildings seemingly all awry; from this height the distant throbbing which had long accompanied us was naturally more marked but I could not myself assign any specific direction to it. I had noted however, that the great broad central highway which had led us into the plaza continued out of it at the far side and that it pointed almost directly north. Along this the eternal warm wind blew steadily into our faces.
The outlines of the city seemed to fade into the amber- tinted dusk, now that the mist had disappeared, but none of us could make out any specific horizon or even a limit to the boundaries of Croth and my later photographs were to throw no further light upon this enigma. From first to last the exact geographical bounds of the city were to remain a mystery to us. While I photographed and the others noted, Scarsdale had been busy deciphering the inscription on the great portico of dressed stone towering high above our heads. He announced with surprise that the building appeared to be that of the city library and proposed to investigate further.