Thus, then, there did exist a magnet of prodigious intensity in the zone of attraction which we had entered. Under our eyes one of those surprising effects which had hitherto been classed among fables was actually produced.
The following appeared to me to be the true explanation.
The Trade-winds bring a constant succession of clouds or mists in which immense quantities of electricity not completely exhausted by storms, are stored. Hence there exists a formidable accumulation of electric fluid at the poles, and it flows towards the land in a permanent stream.
From this cause come the northern and southern auroras, whose luminous splendours shine above the horizon, especially during the long polar night, and are visible even in the temperate zones when they attain their maximum of culmination.
These continuous currents at the poles, which bewilder our compasses, must possess an extraordinary influence. And it would suffice that a block of iron should be subjected to their action for it to be changed into a magnet of power proportioned to the intensity of the current, to the number of turns of the electric helix, and to the square root of the diameter of the block of magnetized iron. Thus, then, the bulk of the sphinx which upreared its mystic form upon this outer edge of the southern lands might be calculated by thousands of cubic yards.
Now, in order that the current should circulate around it and make a magnet of it by induction, what was required? Nothing but a metallic lode, whose innumerable windings through the bowels of the soil should be connected subterraneously at the base of the block.
It seemed to me also that the place of this block ought to be in the magnetic axis, as a sort of gigantic calamite, from whence the imponderable fluid whose currents made an inexhaustible accumulator set up at the confines of the world should issue. Our compass could not have enabled us to determine whether the marvel before our eyes really was at the magnetic pole of the southern regions. All I can say is, that its needle staggered about, helpless and useless. And in fact the exact location of the Antarctic Sphinx mattered little in respect of the constitution of that artificial loadstone, and the manner in which the clouds and metallic lode supplied its attractive power.
In this very plausible fashion I was led to explain the phenomenon by instinct. It could not be doubted that we were in the vicinity of a magnet which produced these terrible but strictly natural effects by its attraction.
I communicated my idea to my companions, and they regarded this explanation as conclusive, in presence of the physical facts of which we were the actual witnesses.
“We shall incur no risk by going to the foot of the mound, I suppose,” said Captain Len Guy.