The young woman descended and began to negotiate the tunnel, amid the oozings of the icy water that had filled its whole length a moment before.

Thus she emerged in the warrior’s crypt, just below the normal level of the pool whose initial draining, due to the manipulation of the second spring, had caused the tunnel to empty. By walking carefully along the gentle slope of an inner jetty, she reached the floor of the cave itself — and was able to approach the prisoner and drag him from his heavy slumbers.

Aag was quite overwhelmed by the story and impressed, despite himself, by the relationship established at the last moment, in his dream, between Christel and that white dove he had imagined brushing by as he felt the liberating touch that had awoken him. Both were cases of basely persecuted innocence coming, in the hour of victory, to rescue the very instrument of its ills and perils.

While he was giving himself up to these reflections, Christel, by the same sloping jetty, had regained the underground passage that opened in the pool’s damp wall and made a sign for him to follow her.

After a silent journey they both emerged through the mysterious exit hidden in the castle vaults. By the successive operation, first to the right, then to the left, of two hitherto unemployed springs at the very foot of the wall, coinciding vertically with the two previous ones, Christel first of all caused the return of the water, which reached its former level, showing that the pool in the cave was once more filled to the brim — then the descent of the slab, whose even mass tightly filled the narrow, hidden opening. The young woman admired the architect’s foresight of old in contriving this secret passage, useful for some desperate escape, even when an ordinary door — free from rock falls but easy for an intelligent invader to block — had been all that separated the crypt from the castle. In her mind’s eye she visualized the hidden machinery whose operation had been exhibited by means of various sectional views, and an accurate commentary in the text, in the documents from the library that she had leafed through some hours before: a subterranean channel linked the cavern’s pool to Lake Mjösen, which lay at exactly the same level three kilometers east; all the time the second spring was being pressed, it released the jet of a hydraulic duct into a container which became heavy and descended, functioning as a counterpoise; this set a delicate system of rods and levers in motion to obstruct the narrow channel, simultaneously opening an overflow drilled two meters down in a wall of the pool, which at once began to empty itself partially into a natural well. It was then, as a result of the water subsiding, that communication became possible between crypt and castle. The third spring, pressed hard, temporarily forced open the resistant plug, worked by automatic compression, of an outlet contrived in the bottom of the container; this was promptly unballasted of all its liquid and returned to its original position — while the rods and levers undid their earlier work by stopping up the overflow to the well and opening the narrow channel through which Lake Mjösen once more filled the pool. The first and fourth springs, moreover, set the flagstone in motion by an analogous system of water counterpoises alternately filling and running dry.

After leading the warrior through darkened stairways, Christel opened the doors to the perron, then the gates of the park, with two keys obtained beforehand, giving her assailant at once full liberty and full pardon.

Instead of availing himself of such a tempting chance to carry out the kidnapping that was to have made his fortune, Aag was prompted by the eleven brothers’ change of heart related in the Kaempe Viser to throw himself at Christel’s feet and express his gratitude and repentance. Then, as the young woman returned silently to her quarters, he made off into the night.

Adopting this subject, which provided him with the desired murky crypt, Canterel chose a very bare site in his park, where the breezes that blew across it were observed to be remarkably changeable in direction. These continual changes could not but favor the numerous comings and goings the punner would have to make in executing the picture. He had the whole area which he intended to use made perfectly and absolutely flat — then waited patiently for his forecasts to show a future period, beginning at the end of one sunset, of two hundred and forty hours without rain or storms. For the experiment would be inconceivable in excessive wind, and a shower, heavy or otherwise, would have upset many of the calculations by making the aerostat’s envelope heavier and by dimming the mirrors and the lens.

When the time came, he brought the aerial paving beetle to the place where the breezes blew, together with a large crate containing the teeth extracted since the discovery of his two magnetic metals. There, with his meteorological predictions before him, he devoted himself during one whole night to the appalling labor of accurately sorting out the many subtle shades of his dental material; this he did by the strange, prodigious light of a special lamp he had recently invented, which had revolutionized the world of studios and academies by enabling any painter to work with the same confidence after the stars had come out as by full daylight. He had deliberately set aside the evening as the starting point of the hour hand’s twenty prophetic revolutions, so as to spend the long hours of darkness at his complex preparations. This would necessarily be a time of idleness for the punner which, by starting work on the following dawn and finishing it on the evening of the tenth day, would avail itself of all the utilizable daylight within the forecasted period, without losing any of it.

Careful not to waste a moment, he set about planning the genesis of his work of art, glancing from time to time at a sketch in oils, made to his specifications by a careful portrait painter, who had laid on a varying amount of each color according to the number of teeth or roots it represented. Leaving the site of the future mosaic empty, he sprinkled the constituent teeth of every shade around it, ready to be snapped up in the paving beetle’s various peregrinations. The teeth were judiciously disposed beforehand in the precise orientation their various contours assigned them in the picture; similarly with the roots, which were always separated from their crowns on the spot, being cut off with a little saw designed for the purpose.

In conjunction with this absorbing activity of sowing teeth, Canterel regulated, to nearly a thousandth of a second, the delicate gears of a special supplementary motor mechanism with which he had provided each of the nine chronometers; once wound up, they would run for a full two hundred and thirty-three hours — a precautionary period somewhat longer, in view of the year’s solar phase, than the time the venture was to take between its first dawn and its final dusk.

When a breeze was due to spring up in a given direction, at a certain fraction of a minute, the lens, moved by its special chronometer, would concentrate the solar rays upon the yellow substance — maintaining its calorific position for a longer or shorter period which would depend on the clarity of the atmosphere, the thermal power of the sun (proportional to the curve of its evolution) and above all on the relative opacity and length of occultation of any cloud that passed over its burning disc. In the part of his labor connected with the lens, the professor once and for all allowed for the fine shadows cast on the ocher substance by some of the silken threads of the net.

A great deal of hard work was involved in the regulation of the valve’s chronometer. As a violent gust might well have carried the paving beetle away while it was at rest, it had to be partially deflated now and then, quite apart from its aerial peregrinations, solely for the purpose of making the whole apparatus heavier with a view to greater resistance and stability. This fact would have a direct repercussion on the function of the lens, which would be obliged to dazzle the yellow substance for a longer period in order to make up the lost hydrogen.

Lower down, the work of the two discs dedicated to attracting and releasing the teeth was easier to regulate. On the other hand, the adjustment of the three chronometers belonging to the inner extensions of the claws involved Canterel in appalling calculations. As for the mirrors, their perfectly regular motions were designed merely to follow the sun’s path; each day their overall orientation would be changed a little on account of the daily alterations in the sun’s apparent path caused by the inclination of the plane of the equator to that of the ecliptic.

Between sunset and sunrise the apparatus always had to remain stationary and quite untouched, for the chronometers would be set in advance, up to and including the last day. Their dials were deliberately left visible so that it would always be possible to know that their movements were free from the slightest irregularity and were continuing to function properly, giving the correct time.

Canterel finished his preparations at cockcrow, then, to balance the aerostat, filled it with a basic supply of hydrogen obtained in the ordinary way, without using the ocher substance at all. By profiting from every caprice of the wind, the paving beetle was to complete the mosaic by nightfall on the tenth day, and it would exactly reproduce, on a larger scale, the sketch done in oils, except that four thin lines would be missing, one from each side. However, the insignificant absence of these lines would not harm the subject as a whole, and was deliberately chosen in preference to anything else. As, perforce, they would not be used, the teeth originally destined for the picture’s extreme outer edge were left out and thrown away. Then the professor, who had publicly announced his plans, threw open the gates of his estate so that witnesses might come at any time to watch the device making its aerial trips and verify the complete absence of any deception. Around the fascinating spot, a cord was stretched over low pegs to form a polygonal barrier designed to keep visitors far enough away to prevent any perceptible interference with the breezes. Finally the punner was poised over a cream eyetooth, waiting for a moment to make use, motu proprio, of the first favorable breath of wind.

The experiment, now nearing its end, had already lasted seven days, and so far, thanks to the marvelous adjustment of its chronometers, the itinerant device had always conveyed teeth or roots to the intended places.