Since their arrival on Mars Robert and Professor Palmer had established the existence of the canals, or ducts, thereby settling for all time—provided they succeeded in returning safely to Earth—the controversy over the most noted characteristic of Mars as seen from the Earth, the curious network of lines. Incidentally, they had seen the Martian deserts as well as both rural and city life on the planet. They were informed as to the correctness of their original conjecture as to the method of pumping the water from the poles to all sections of the globe. This was accomplished by means of electric pumping stations at intervals along each duct, the rays of the sun being absorbed and converted into electric energy for this purpose by the big checker board structures.
But the feature which, so far, had defied plausible explanation by all experts of our world, still remained a riddle to the adventurers. This was the “carets,” or triangular-shaped points which existed wherever the canals were seen to connect with one of the large, shaded regions.
These shaded regions also were a riddle. A theory that the latter were seas was exploded by the fact that in some instances the canal lines were visible running across them. For another thing it was agreed by practically all experts that the seas on Mars had long since dried up.
It was, therefore, with considerable excitement that Professor Palmer observed that they were nearing one of these regions. From a height of several thousand feet one of the “carets” could be seen plainly as they approached it.
As Robert lowered the Sphere toward it, Hakon showed signs of uneasiness. Still he held his peace until it became quite evident to him that his hosts intended approaching close to this section. Zola, too, was evidently perturbed.
“There is danger there, gentlemen,” said Hakon, finally. “I beg of you, do not go too close.”
“What is it?” questioned Professor Palmer, now intensely interested. Both he and Robert received the impression that some terrible physical force connected with the phenomenon threatened their safety. But in this they were quickly disillusioned by Hakon.
“We are now in the region of the usurper’s strongest support,” he told them. “It was the hotbed of traitors before he stole the throne, executing many of my loyal leaders. These people have, no doubt, been notified to be on the lookout for us and will try to destroy us with their hilwai if we approach within range.”
Hakon explained further that hilwai were a kind of large gun, electrically operated, in lieu of the obsolete kind in which explosives had been used in previous centuries, before the planet’s mineral supply had been virtually exhausted. These guns had a range of about twenty miles horizontally. Though this was not a very great distance, considering the weak gravity on Mars, it was sufficient to make it uncomfortably dangerous for them if they undertook to view the “caret” at close range.
Hakon was surprized to learn of their curiosity regarding the dark blotches and their caret-shaped junctures wherever they were joined to a canal, and readily explained this phenomenon.