A great deal of work had already been done in that region, and also over the entire course of the Great Current. The thousand cables, each containing ten thousand elements, in which the electrical current would circulate between the North Pole and the tropics, had been laid. It was now necessary to take advantage of the eight or ten weeks during which the soil, laid bare by the melting of the snow between Scoresby and the Franz-Josef fjord would be sufficiently dry to permit the works to proceed.
The last section to the north of Scoresby was about two hundred and eighty kilometers, a distance that would have seemed enormous, in that ingrate latitude, to the people of the twentieth century, but did not frighten the engineers of the Great Current, equipped with the extraordinarily powerful means of the twenty-third.
The cables were constructed to admit a current of twenty thousand amps under half a million volts, equivalent to a power of ten million kilowatts. In order to carry such an amperage, the bundled conductors of each element had to measure about ten thousand square millimeters in section—which is to say, about 113 millimeters in diameter.
In order to make their manipulation easier, the groups of elements—called cables for the sake of brevity—were not disposed in cylinders but sheets of two hundred elements, fifty such sheets being arranged one of top of another. The breadth of an element, formed of two bundled conductors, being 226 millimeters and its height 113 millimeters, each cable measured, in its rectangular section, forty-six meters in breadth, taking account of the thickness of the insulating envelopes, and about five meters seventy in height.
A cable of that sort weighs more than 1,200 tons per meter, and it would have been a very difficult task to lay it completely assembled, but they proceeded in several steps. The elements were posed separately, in segments of a hundred meters, which were assembled in place one by one. At sea, they were sunk like simple telegraphic cables and then grouped into bundles under water, with the aid of submarines and diving automata.
In the terrestrial sections the sheets were assembled by simple ligatures, which it would be easy to undo in order to expose the successive layers if any repair became necessary.
In Greenland, from the Franz-Josef fjord to Scoresby, the cables were lodged in groups of ten in galleries of reinforced concrete, comprising eleven spans, with columns and arches to support the vaults. Those tunnels were very robust, in order to resist the enormous pressure of the winter snows.
On the eleven spans, ten, each measuring fifty meters in width, were occupied by the cables, or groups of elements, which rested in a basin between two sidewalks permitting easy access to all points of the line. Numerous mobile gangways, running on longitudinal rails, served for the inspection and maintenance of the cables.
The five spans to the right and the five to the left were equipped in that fashion on exactly the same plan. The central span, the presence of which brought the total number to eleven, was reserved for circulation. Twenty-five meters wide, it contained a railway with two parallel tracks separated by a twelve-meter platform. The electric energy that ensured the movement of the trains was to be extracted from the Great Current; until that was ready to function, the first vehicles used for transportation of materials in the tunnels were powered by energy from a large turbine factory installed at Scoresby, which employed hydrogen as a fuel.
Each gallery of eleven spans, including the thickness of the intermediate arches, the supporting walls and the external buttresses, was about five hundred and fifty meters wide. As it required a hundred similar galleries to lodge the thousand cables of the Great Current, and it was necessary to reserve spaces between them for the flow of water produced by melted snow in winter and summer, the ensemble occupied a width of sixty kilometers.
That sixty-kilometer-wide track continued southwards from Scoresby on the sea bed, where the cables were protected by a reinforced envelope. At the junction with the coast, they were conducted as far as a level to which the ice never extended, through completely watertight reinforced concrete channels.
All these works, which Chartrain had only followed at intervals, occupied as he was with the installation of cables between Iceland and Great Britain and on the territory of the latter country, were almost complete, thanks to the enormous apparatus, served by a considerable fleet, that had been put to work.
The young engineer had the opportunity to obtain a view of the ensemble when he went in a helicopter with Professor Gainsworth from Scoresby to the Franz-Josef fjord..
Entirely uncovered, under the summer sun, which never sets at the latitude of Scoresby at that time of year, the tunnels, some of which had only been completely closed for a few days, were lined up with impressive regularity at the foot of the snow-crowned coastal mountains, from which water was flowing in thousands of torrents
The flow of those waters in spring and summer had been one of the most difficult problems to solve. In many places it had been necessary to construct passages, either for artificial channels or for the natural beds of the streams. The hundred galleries had to cross as many bridges, many of which were extremely bold. In places, the galleries were staged on the sides of the mountain, and then took on, along with their viaducts, a grandiose appearance.
In truth, it was the work of titans that was displayed to the eyes. How many tons of metal had it been necessary to extract from the bowels of the earth? How many factories had worked incessantly, at full power, for years in order to fabricate the cables that were extended in thousands over the globe? How many quarries of stone and cement had been emptied to construct so many dykes, walls, tunnels and bridges?
Along the entire length of the Great Current, there had been no other region in which they had been forced to employ such prodigious efforts, but it was a matter of overcoming a nature more hostile than anywhere else.
The helicopter in which Chartrain had taken his place along with his chief and his colleagues flew for some time over the Franz-Josef fjord, because Professor Gainsworth wanted to take account for himself of the condition of the ice.
The fjord, which had been chosen for that reason, was the ultimate outlet of numerous glaciers that descended from the largest mountainous massif in Greenland. In that season, the speed of the glaciers’ flow reached nearly twenty meters a day, which was relatively considerable. They came together in the immense valley constituted by the fjord, and collided, exerting formidable pressures on one another, which caused the ice to break up, lifted it up, bristling with seracs, hollowed out crevasses and dislocated it, while deafening detonations, mingled with the thunder of avalanches, rose from the chaos.
As the helicopter had to fly low because of the clouds rolling over the bay and masking the mountain-tops, the passengers could hear the din of the ice very clearly in spite of the hum of the propellers.
The vast and chaotic frozen surface of the fjord reacted intensely on the atmosphere above it, determining violent eddies into which the helicopter was drawn. In spite of the skill of its crew, the machine was subjected to abrupt ascents and descents, which the passengers found very disagreeable. The captain even thought that he ought to advise Professor Gainsworth that it would be dangerous to prolong the excursion; the overworked crew might make a false move that would end in catastrophe.
It was therefore decided to return to the base, going around the mountains at the extremity of the fjord. When the helicopter headed out to sea, the passengers were able to contemplate the front of the glacier, an enormous white, green and blue cliff that blocked the valley over a breadth of four or five leagues, and from which blocks dislocated by the pressure never ceased to detach themselves.
The captain, who was accustomed to flying in the region and had often witnessed the spectacle, drew the attention of the engineers to an immense vertical crevasse that split the ice-cliff.
“If I’m not mistaken,” he said, “we’re about to witness the birth of an iceberg.
He had the propulsion helices stopped, and the helicopter remained suspended five hundred meters in advance of
the front of the glacier, two hundred meters above the level of its crest.
“It would be dangerous to hover any closer,” he explained. “You’ll understand why shortly, if what I anticipate actually occurs.”
Professor Gainsworth and his colleagues armed themselves with binoculars in order to observe the phenomenon.
Formidable cracking sounds were heard, and they saw the crevasse slowly widening. Blocks ten or fifteen meters in height were detached all along the fissure, falling and colliding with one another, raising enormous waves and sprays of foam.
“Fantastic!” murmured Chartrain.
But the captain laughed and said: “You haven’t seen anything yet.”
A quarter of an hour passed during which the crevasse was further enlarged, while others formed, parallel to the first, and the fall of the blocks continued. Then the glacier trembled, an entire section twenty meters high and five hundred meters wide was detached from the cliff noisily. A veritable iceberg, a mountain of ice this time, perhaps a hundred cubic meters, fell obliquely into the sea, which splashed almost to the height of the cliff.
The captain had given an order. The suspension helices, giving full power, drew the helicopter upwards while the propulsive helices pushed it out to sea, because it was necessary to avoid being sucked in by the atmospheric disturbance that was inevitably about to be produced.
Indeed, in spite of the rapidity with which it had drawn away, the apparatus was forcefully tossed about, and for several seconds it followed a violent roller-coaster trajectory.
The iceberg and the front of the ice-sheet had disappeared behind an enormous veil of mist, but beneath the helicopter the sea was seething, white with foam between the blocks of ice that encumbered it, and which seemed to be prancing like a host of clumsy giants.
The helicopter circled at the entrance to the fjord until the mist had dissipated, and the floating mountain of ice could then be seen drawing slowly away from the cliff from which it had been detached. It only projected above the waves by a hundred meters, which was still very respectable and gave an idea of its enormous volume when one knew that the submerged part was five times as large as the part above the surface.
The passengers in the helicopter had not reached the end of their excitement, for they suddenly saw the iceberg oscillate. The inferior section below the surface must have split; its equilibrium had been modified and it was shifting in order to return its center of gravity to its normal position.
A four-hundred meter mountain performing a pirouette is not a banal sight.
A further revolt lifted up the howling sea; the floes began to prance again; a new veil of mist rose up, hiding the image of chaos from the spectators.
Accustomed as they were, by virtue of the progress of science and technology, to the domination of nature, the engineers of the Great Current who had just witnessed that grandiose manifestation were affected by it. Chartrain had a moment of doubt: was it not presumption on the part of humans, those pygmies, to attack such prodigious forces?
The passengers scarcely exchanged a few words before landing at the Franz-Jozef base.
There, they inspected the works in progress.
At that end of the line, the problem consisted of establishing, between the extremities of the elements and the ice that descended from the mountains and accumulated in the depths of the fjord, a contact sufficiently narrow to profit fully from the source of cold constituted by that immense natural reservoir.
They had thought of hollowing out approach conduits for each cable, the inferior extremity of which would terminate below the level of the ice, in such a way as to reach the frozen mass. Those conduits would be distributed along the entire length of the fjord. Thus, each cable could spread out, displaying its elements, in order better to capture the cold, over a conveniently-adapted broad surface.
To that effect, they had hollowed out a frontal tunnel parallel to the coast of the fjord, into which all the conduits opened. The materials produced by the excavation of the rock had served for the construction of the surface tunnels between Scoresby and the fjord.
It only remained now to establish a powerful framework in the frontal gallery, partly in iron and partly in reinforced concrete, the different traverses of which, disposed obliquely and terminated externally by enormous rostra, would be orientated contrary to the ice current, in much the same fashion as the prow of a ship is toward the waves when heading into a tempest.
Driven by the pressure against that skeletal system, the ice would be broken up by the spurs and slide between the traverses, which it would invade, gradually filling the tunnel. The extremities of the cables would have been divided up in the framework, the elements being lodged along iron beams in grooves designed for that purpose.
The whole of that construction would initially be carried out under ground, shielded by a wall of rock of sufficient thickness, which had been reserved and allowed to persist until the very end. When everything was complete, the wall would be demolished and there would be nothing more to do than await the invasion of the ice.
That plan had been adopted in spite of objections that had been opposed to it, the most serious of which was based on the irresistible force of the ice current. The project’s detractors claimed, in fact, that the framework, no matter how solid it might be, would be carried away by the moving glaciers. The response made to them was that the pressure of the ice would be limited by the intense fusion that would be produced in contact with the cables under the action of the electric current, restoring at the polar extremity of the line the heat obtained at the other extremity in the tropics. For that was the entire secret of the gigantic enterprise: to melt the polar ice with heat obtained from the tropics.
It has been calculated that about twenty thousand cubic kilometers of ice is detached every year from the region of the North Pole in spring and summer. If one assumes that the figure is approximately the same for the South Pole, that is forty thousand cubic meters of ice that the Earth fabricates every year and then disperses in warm waters, where that enormous mass melts and disappears.
It is necessary to imagine the enormity of the loss of energy represented by that natural mechanism.
In order to liquefy without changing its temperature, a kilogram of ice, at zero degrees, absorbs a little more than seventy-nine kilocalories—which is to say, the quantity of heat required to raise the temperature of a liter of water by seventy-nine degrees. Now, that quantity of heat is equivalent to a considerable amount of work. It is theoretically sufficient to expend one kilocalorie to raise a weight of four hundred and twenty-five kilos to a height of one meter. The quantity of heat absorbed to melt a kilogram of ice is therefore equivalent to the effort required to raise a mass of thirty-three metric tons to the same height of one meter, or a weight of a hundred and ten kilos to the height of the Eiffel tower.
If one calculates on the same basis the quantity of energy absorbed by the melting of the forty thousand cubic kilometers of ice that the poles reject every year, also taking account of the heat absorbed in rising the temperature of the melt water, and that of the ice when it is older than zero degrees, one arrives at a figure of one thousand six hundred quintillion—sixteen followed by twenty zeroes—kilogram-meters.
The imagination cannot estimate such a number, but one can nevertheless form an idea of it if one thinks that that work is carried out over a year of three hundred and sixty-five days—which is to say, thirty-one million five hundred and thirty-six thousand seconds—which represents a little more than five trillion kilogram-meters per second, or nearly seven hundred billion horsepower: a thousand times the hydraulic pressure developed in the entire world by streams and rivers.
One can understand why the people of the twenty-third century were obsessed by the desire to utilize that enormous amount of wasted power—and after having envisaged the fantastic figures on which their ambition was founded, one can deem as modest their initial attempt, which was only a matter of making use of the ic
e rejected by the Franz-Jozef fjord, at a rate of eight or ten cubic kilometers a year. But the melting of ten cubic kilometers of ice is equivalent to a hundred and thirty-three million horsepower: twenty-two times the hydraulic power of France.
The game was worth the trouble of playing.
Certainly, they would only use in the beginning a tiny fraction of the total latent power that the great source of cold would draw from the equator, but if the first installation produced the results for which they hoped, they would hasten to construct others, which would rapidly multiply tenfold, and then a hundredfold, the energy resources obtained in that manner from the great animator of all life and all movement on the surface of the earth: the Sun.
IV
Paul Chartrain went into the special telephone and television cabin that had been installed at the Franz-Josef base for communication with Europe and Africa, particularly with the tropical section of the Great Current enterprise, which was working on the completion of the factories capturing the solar heat.
After extremely careful studies, the region of Timbuktu, in the vicinity of the seventeenth degree of north latitude, had been chosen for the installation of the hot base of the Great Current. The climate of that region is relatively constant; the temperature is maintained there between the narrow limits of twenty and forty degrees above zero, and rain is rare. The apparatus for the condensation of solar heat there could thus be designed to respond to a regular regime, which is an eminently favorable condition for an industrial installation.
In addition, the access routes were excellent; as well as the river route of the Niger, which had been continually ameliorated by major works during recent centuries, they had the Transsaharan and the Dakar-Timbuktu-Chad-Zanzibar railways at their disposal.
There would not have been any advantage in moving closer to the equator. The climate would have been less regular, communications more difficult, and what they would have gained in terms of the quantity of heat absorbed during the dry seasons would have been largely canceled out by reductions of yield in the major and minor rainy seasons.
An International Mission to the Moon Page 15
