Nanga Parbat, 1932
Nanga Parbat, 1932
ON April 28, 1932, the German American Himalayan Expedition sailed from Genoa for India to attempt the ascent of Nanga Parbat.1
Nanga Parbat is the seventh highest mountain in the world, so that if the expedition had been successful, it would have attained a summit higher than any yet reached by man. The mountain stands, a tremendous isolated massif, northwest of the Vale of Kashmir in the extreme western end of the Himalayas. The dozen or more clustered peaks of its ridges and shoulders rise to a central peak 26,630 feet above the sea.
Nanga Parbat is a mountain rich in traditions, worshipped and feared by the natives of all the surrounding country. Its name in Urdu means “Naked Mountain,” probably from the bare rocks of its tremendous precipices. In the Dard, the local language, it is known as “Diamir” or “The Abode of the Fairies.” The legends of the region relate that the fairies live on the mountain, and take with them certain chosen mortals to share their immortality.
Only one serious attempt on the mountain had ever previously been made. In 1895 A. F. Mummery, the great English climber, entered the region with a party consisting of J. Norman Collie, G. Hastings, and General C. G. Bruce. They made first ascents of surrounding mountains and a reconnaissance of Nanga Parbat and decided to attack it from the northwest, from the Diamirai glacier. Mummery, climbing alone with two coolies, here reached a height of over 20,000 feet, when he was obliged to return because of the illness of one of the coolies. The rest of the party then started around over the lower ridges, to make another attempt on the mountain from the Rakiot glacier. Mummery was to go the shorter way over the Diama Pass and meet them. He started off with two coolies. None of them were ever seen again. It is probable that they were buried in an avalanche.
Nanga Parbat had been chosen by the Expedition because it seemed to offer better hopes of success than any other of the greatest peaks. It is comparatively easy of access; it escapes the handicap of the monsoon, which is not felt to any extent in the western Himalayas; and though it had been very little investigated from a mountaineering point of view, it seemed to offer several possible routes. Mummery’s explorations had shown that the south side, a tremendous wall of 15,000 to 20,000 feet, was practically impossible, and an approach from the east or west would involve going over a great chain of the minor peaks of the massif to reach the summit peak. But, from all information obtainable, there appeared to be good hope of possible routes from some one of the nullahs of the north or northeast.
The expedition was made up of nine members, with Willy Merkl of Munich as leader. E. Rand Herron2 of New York was the one American climbing member, the first American to take part in any of the great post-war Himalayan climbing expeditions. I was the other American member, my official position being that of newspaper correspondent. I also acted generally as “Proviantmeisterin,” and did all sorts of odd jobs. The other members were Fritz Wiessner of Dresden and New York; Peter Aschenbrenner of Kufstein, Austria ; Fritz Bechtold of Trostberg, Bavaria; Herbert Kunigk of Munich; Felix Simon of Leipzig; and Dr. Hugo Hamberger of Rosenheim, Bavaria, as physician.
The expedition arrived in Bombay on May 9, and travelled as directly and speedily as possible to Srinagar in the Vale of Kashmir. There we established ourselves for a week, living picturesquely in houseboats on the Jhelum River, buying equipment and engaging ponies and servants.
During this week we went through a time of great uncertainty and uneasiness. Owing to complicated misunderstandings, we had not in Europe obtained the official permission to enter the District of Chilas, in which the north side of the mountain lies. Permission to visit this district is difficult to obtain, partly because the Chilas tribes are a restless people, only comparatively recently pacified, and the passage of Europeans with an army of coolies might cause disturbances, partly because the district is too poor to have enough food to be able to feed such an expedition passing through.
Therefore, we waited in Srinagar, hoping daily for the desired permission. At last we received word from the government that although we might visit the south side of Nanga Parbat, entrance into the Chilas district could not be allowed. However, we hastened to make fresh representations, promising that we would take with us all our own provisions and food for coolies, and would keep to the higher slopes of the mountain, avoiding the inhabited valleys. The government then readily granted the desired permission.
So on May 23 we set out from Srinagar, following the main caravan route to Central Asia, and in nine days made our way, with pony caravan of about a hundred ponies, to Astor. En route we were obliged to cross the main range of the Himalayas. This involved going over the Burzil Pass, 13,775 feet. At the end of May it was still deep in its winter snow and had not been crossed this year. It was thought, therefore, that it might be necessary here to change to coolies. But the pony men volunteered to attempt it with their horses. We started at two o’clock in the morning, to travel as much as possible while the snow was still frozen hard. Twelve miles of snow lay ahead of us. It was a steep slope to the top of the pass, and even at night the ponies broke through occasionally into soft snow, so by sunrise we had not even reached the top. From then on, the difficulties increased rapidly. As the snow softened in the sun, the ponies were wading deeper and deeper, until in the worst places they wallowed halt way up their bellies, and often it would be necessary to unload them, before the pony men could haul and push them out on to somewhat firmer going. It was twelve hours of the hardest kind of work before we reached dry ground again on the other side of the pass, at Sirdar Chauki. There we found a telegram awaiting us from the friendly road contractor at Gilgit. It read “Burzil Pass not yet passable by ponies.”
The rest of the trip was without incident, but continually picturesque. We passed or met many caravans of black-mustached. turbaned Kashmiri from the plain, or Mongols returning to Turkestan, flat-faced men. wearing peaked caps edged with fur, and dull red quilted coats, and riding astride piles of skins and embroideries. We went through little hill settlements of round stone houses with mud roofs, where dark-faced women stared at us from under tambourine-shaped hats fringed with silver ornaments. Here, too, were the hill men in full gray wool cloaks, with little round caps—the sort of people who were to be our coolies all summer.
At Astor we arranged for the change from ponies to coolies, and hired 120 Astori and 40 Baltis. From Astor on, for the rest of the summer, we had the invaluable aid of Leftenant R. N. D. Frier of the Gilgit Scouts, lent us by the Political Agent at Gilgit, to act as our transport officer. We continued a day to Doyan, still by pony, and were joined there by our Balti and Astori coolies, to start the long trek over three 12,000- to 14,000- foot ridges to the base of the mountain. There, also, came our thirty Hunza porters to climb with us on Nanga Parbat. They were sent from the Hunza district, high up among the hills to the north. At first it had been thought that we might import porters from Darjeeling, but we were told that the Hunzas should make very good high-altitude men. This did not, however, prove to be the case: we had trouble with them from the beginning to the end of the summer.
The journey of the next two weeks to the base involved elaborate plans of carrying our loads by relays, as we had not enough porters to move them all together, and proved full of difficulties with coolies and of every sort of transport complications. As this region had previously been little explored, the route we followed had to be scouted out by two of our climbers, who went on two days ahead, traveling fast and light, and sent us back frequent word. Aschenbrenner and Bechtold acted as scouts for the first part of the route, and later Aschenbrenner and Kunigk.
The way took us over the ridge above Doyan and down its almost precipitous sides into the deep V-shaped valley of Leychar Nullah, up over the next ridge and dropping down equally steeply into Buldar Nullah. Here we camped two days, while Herron, Bechtold, and Hamberger explored the Buldar glacier, for a hopeful-looking point of attack for the mountain. They returned unsuccessful, and we continued over one more ridge into Rakiot Nullah, the lower part of which is known as “Tatto Valley.”
In spite of coolie troubles it had been a pleasant journey, through beautiful and idyllic country. The lower slopes of the nullahs were full of groves of fine evergreens, and meadows bright with early spring flowers. On the ridges the winter snow still lingered. Our second camp in Rakiot Nullah was christened the “Fairy Tale Camp,” because of its amazing charm. Our tents were pitched beside a clear little brook on a meadow surrounded by pine trees and blue with forget-me-nots, and above towered, gleaming white, the magnificent north face of Nanga Parbat.
Here we received the final word from the scouts, who had now been close to the mountain and had made a first ascent of an unnamed 16,000-foot peak, to look over possible routes. They wrote “Rakiot glacier will surely go, according to our opinion. … We favor attacking it here.” We therefore established a base camp at the edge of the treeline. (It later was moved, two and a half hours farther up, to a bare grassy plateau [12,400 ft.] between two glaciers, just at the foot of the ascent.)
On our arrival at this lower base camp, where loads were finally collected, and could be checked over, we made the disastrous discovery of the loss of seven bags of porters’ equipment. Mr. Wiessner’s paper, which follows, describes this loss in detail, and all of the difficulties which it caused. It was undoubtedly one of the major causes of our defeat.
On June 24, Herron and Kunigk started out from the lower base camp for the first scouting directly on the mountain. The two men who had gone in advance had seen what seemed to be a way, leading, first, through a badly broken-up icefall, and, later, winding up steep snow slopes among seracs to a high plateau just below Rakiot Peak with Rakiot Ridge beyond it. This ridge, if reached, could apparently be followed to the saddle between Northeast and Northwest Peaks, and thence to the summit. The two apparent problems presented by this route were getting through the first icefall, and later somehow getting around or over Rakiot Peak to the ridge beyond. If these points of obvious difficulty could be successfully passed, the route appeared to offer good hopes of victory. The first task, then, was to see whether there was a way through the lowest icefall. This was the purpose of Herron’s and Kunigk’s scouting trip.
The first night, the two men spent in the lonely meadow which was later to be our base camp. Just beyond, to the south, rose the “Great Moraine Hill,” between them and the mountain, shutting off all view of the route ahead. Next morning about six they started, and climbing in half an hour the small moraine ridge to the southwest, were able without bergschrund difficulty to get onto a little glacier by following which they could reach the main Rakiot glacier.
It was their first experience with Himalayan climbing, and they had wondered how it would differ from that in other ranges. But this glacier seemed entirely natural. They had been specially warned of avalanche dangers. Himalayan avalanches are, of course, tremendous and terrible in their size and in the distance that they travel, and Nanga Parbat is noted even among the Himalayas for its avalanches. The climbers saw them, as expected, thundering about every half hour down the great north face of the mountain on their right. Sometimes 15,000 or 20,000 feet they would fall, roaring like express trains, pouring in huge water falls down the cliffs, sliding down the snow slopes, gathering speed and volume as they came, and finally spreading themselves in tremendous fans over the flat glacier, with a great wind going before them, and clouds of snow dust rising as they fell. The two men kept well toward the left-hand side of the glacier, as far as possible from these avalanches. Thus they reached the little moraine ridge that separates this minor glacier from the main Rakiot glacier, up which they were to continue climbing from its comparatively flat lower part into the icefall. It was now about ten o’clock. They had come along well, and the icefall did not look far away. They thought they could easily finish their scouting in a day. So they sat for some time on the moraine ridge, pleasantly resting and discussing esthetics. After a while they started on.
They were now to find some of the differences in Himalayan climbing. They began to feel the altitude, which was from 15,000 to 16,000 feet; the June sun at that height and latitude poured down a burning, dizzying heat, which made them faint and sick in spite of sun helmets; and this heat was also softening the snow, till it became softer and deeper than any Alpine snow they had ever experienced. They plodded on more and more slowly. And now they began at last to discover the tremendous size of these mountains. They had judged the distances by Alpine standards. Here the proportional relations of things were the same—a serac to a glacier, a glacier to a mountain—but everything was done on a gigantic scale.
About noon they realized that they would have to bivouac, and left their packs at a good spot. Here, to combat the still- softening snow, they put on snowshoes, the heavy German ones. These helped slightly, but proved troublesome because of the steepness.3 In a short time they saw that they could not even complete their scouting before night. They must return to their bivouac place, and go on again next morning.
As they had not really expected to bivouac, they had with them nothing but a small light tent and a can of Ovomaltine—no sleeping bags, no cooking things, and no water. They lay stripped and panting, in the little tent, unbearably hot in the afternoon sun, and melted snow for water by stuffing their canteens full and holding them against the sun-heated sides of the tent. They tried to repeat this process later, in the night, by putting a canteen between their two bodies, but found it too chilly a bed fellow. As the sun went down, the overpowering heat vanished, and it became bitterly cold—so cold that they could hardly sleep. They were very hungry and spent most of the night eating Ovomaltine raw. Next morning both of them found themselves rather sick. But the scouting must be done, so they went on. They made a way among the giant crevasses and seracs, to the little plateau which had been picked upon as a possible spot for a camp. Then they returned.
Now that the route was found, the first two camps were speedily established by Wiessner and Simon: Camp I at 15,450 feet just above Herron’s and Kunigk’s bivouac, and Camp II at 17,080 feet on the little plateau. At Camp II an ice cave was dug; and such caves were made at all the later camps. They had proved very useful for Bauer’s party on Kanchenjunga, being warmer than tents to sleep in and safer from storms and avalanches. It was decided during the summer, however, that these caves would not be used another year, for they took a great deal of time and exertion to build, and were very gloomy places to live in. They became mostly storehouses, and overflow sleeping quarters when the tents were full.
Some days later Wiessner and Aschenbrenner were sleeping at Camp I with four coolies, en route to complete the construction of Camp II. They were wakened in the middle of the night by a terrific roaring, coming nearer and nearer. Then the tent poles broke, and the tent caved in on them. They tried to hold it up a little as best they could, to keep from immediate suffocation. But they thought that their last hour had surely come. Gradually, however, the roaring grew less and died away, and they were pleasantly surprised to find themselves still alive. They crawled out, and were clutched at in the darkness by the coolies, crying “Sahib! Sahib!” Their tent also had collapsed. It proved to be from the weight of snow dust from the edge of an avalanche. The coolies could not be calmed all the rest of the night, but spent it praying with clasped hands to the god of Nanga Parbat. Next morning they insisted upon returning immediately to the base camp, and told their story, and all of the Hunzas said they would start back to their village next day and never venture near the mountain again. There were impassioned speeches by their Jemadar (head man) and by Lieutenant Frier, and finally they were persuaded to stay, with the payment for mountain work of five times the originally agreed wages.
After this, for a while, things progressed well. Camp III was established by Herron and Kunigk at 18,350 feet, and Camp IV, at almost 20,000 feet by Merkl and Bechtold. This camp was erected on the edge of the plateau below Rakiot Peak, so that it was possible to look down and watch large portions of the route up, and arrivals at Camps II and III. There was also a magnificent distant view of the Karakorum. As it was to be used as an upper base camp, two ice caves were built. One of them was a very large one, with three sections for sleeping. The architects of the ice caves had vied with one another to make them uniquely interesting. That at Camp II could boast a window opening into cold and darkness, where the diggers had broken through into a crevasse. Camp Ill’s was round, with a large central pillar. But Camp IV’s was the largest and most elaborate of all. The second cave there was used for a kitchen and sleeping place for Ramana, our sturdy, darkfaced Kashmiri cook. Here he spent a month and a half cooking for us and waiting on us, tirelessly, and always cheerfully. He was not even depressed but came next morning to report with a broad smile, “Ramana finish,” when the roof of the cave fell in on him in the night. Though the number of tents varied with the population, there were always at least three, so it was quite a settlement. Because of delays and difficulties it developed that several of the climbers and the writer spent over a month there or higher without descending.
The climbers had now to settle the second and more difficult-appearing problem, the attainment of the ridge beyond Rakiot Peak. Wiessner and Simon believed a route was possible around the base of Rakiot Peak; but it would necessitate going through a very badly broken-up area, with great technical difficulties, and most dangerous from the probability of falling seracs. Aschenbrenner and Kunigk thought that a better route might perhaps be found high over the shoulder of Rakiot Peak. So they made a reconnaissance in that direction, incidentally ending by making the first ascent of this summit, 23,170 feet. They bivouacked the first night just below the main ridge, with Herron and Hamberger acting as porters to carry loads to their bivouac. They then climbed along the shoulder, up difficult rocks slippery with snow and verglas, and so along the ridge to the summit. They discovered no possible route for porters in any of this climb. The dangerous way among the seracs and crevasses would have to be followed.
The next week or two were a time of strenuous effort and frequent misfortunes. Herron and Aschenbrenner started from Camp V (20,800 feet), located just before the difficult region, to find a way through this, and establish Camp VI, but after an hour or two they were obliged to turn back, as Aschenbrenner had developed a badly frozen foot. The feeling did not return in it after three weeks of waiting at Camp IV, and he was not able to do any climbing again that summer. Kunigk was taken sick. His illness later proved to be appendicitis, and he must go down with Dr. Hamberger to the base camp, and on to the hospital at Gilgit, five days away, for an operation. The others went on again to Camp V, and finally cut and forced a way through the seracs and among the crevasses, to establish Camp VI at 22,000 feet, in the lee of a bergschrund, in the amphitheater below Rakiot Ridge.
Here they began to be very definitely troubled by altitude. Of course, even by Camp IV, plenty of altitude symptoms had been felt, but they said that the difference between Camp V and Camp VI was a very noticeable and sharp one. From then on, they had to fight to a marked degree all the regular handicaps—of breathlessness, and feeling of extreme lassitude, and difficulty in making the slightest exertion; and suffered the other extreme discomforts related by climbers at really high altitudes. They remained convinced, however, of the wisdom of their decision not to bring oxygen, because its value did not seem great enough to pay for its weight. Herron and Wiessner, especially, noticed even in their short stay above 20,000 feet that they began to feel the benefits of acclimatization; and all considered it better to depend on such improvement than on oxygen.
Four days’ fighting were necessary to reach Rakiot Ridge from Camp VI. The first day, Herron and Bechtold started off toward the right, but after an hour and a half’s work in snow that reached up to their waists or above, were unable to progress more than a hundred feet or so. The next day, Herron and Bechtold started again, to the left this time. The snow appeared less impassable, but Bechtold almost immediately found himself too ill to go on. Herron, reluctant to let a day of good weather be lost, pushed on up alone. As he was considering the problem of the first bergschrund, well on the way up, he saw Simon, the one other man who had proved well enough to move, following him with a rope. He tied it on, and they continued, fighting through snow gradually getting softer and deeper, and broke a trail part way up to the ridge. There they reached a place where the snow seemed bottomless, and turned back exhausted. The following day they were obliged to go down to Camp IV with very bad sore throats and general exhaustion.
Meanwhile, Wiessner had arrived at Camp VI with two coolies. One of them was so overcome with mountain sickness that he lay all day groaning, and the other refused to go on without him. So the three sahibs, Wiessner, Merkl and Bechtold went on up without coolies or loads, using the trail broken by Herron and Simon the day before. At the place of apparently bottomless snow, Wiessner, leading, was able to get across by half crawling and half swimming. Then the three men at last reached the ridge, returning to Camp VI that night. The fourth day, Merkl and Bechtold carried up a light tent, sleeping bag, and provisions, and Camp VII was finally established at the point reached before on Rakiot Ridge, 23,200 feet. The way to the summit of Nanga Parbat now seemed to lie clear ahead.
They were obliged, however, to come down next day, because of scanty provisions and threatening weather.4 Such a high point was never reached again during the summer.
All of the next month, which we spent mostly at Camp IV, is a wearisome and monotonous story. Through almost all of July, except for one short storm, we had had perfect weather. There were, to be sure, great extremes of temperature, from around 100° F. in the noon sun, to well down toward zero at night. But we had escaped storms and new snow. With the end of July, they began, and continued with maddening frequency throughout August. Nor were they the only problem. Failure of coolies to arrive at Camp IV, failure of sufficient coolie rations, sickness of coolies at Camp IV so that they could not be taken farther—one or another of these troubles occurred in the brief spells of fair weather, and held the climbers back, day after day, while they chafed to push on. As Herron wrote in a letter to a friend, “The month of August was a time of waiting and expectancy, of a chained imprisoned impetus to move and go up. … I was never in my life so spiritually stretched upon one single point—that is, that damnable place up there, so near, to be seen nearly every day only a few miles away, for weeks, and yet so far, in fact never to be reached at all this year.’’
The final misfortune came on August 20, with the failure of coolie rations at the base camp. Then it was decided we might as well all go down, while waiting for rations to be sent for, to give the climbers a chance to rest in lower altitudes before the final push. Certainly, never had grass and flowers looked more beautiful than when we returned to them after over a month in the snow.
Meanwhile, on August 12, Aschenbrenner, Bechtold and Simon had left Camp IV, obliged to go back to Europe by the end of their leave of absence from business. This meant that of the climbers, only Merkl, Herron and Wiessner now remained, with Lieutenant Frier. Now at last Frier must reluctantly go, also to return to his military duties in Gilgit.
On August 28, after more delays of bad weather, everything was finally ready, and a beautiful clear day dawned for the beginning of the final push. At eight-thirty Merkl, Herron and Wiessner started up the mountain with twelve coolies, carrying coolie rations for ten days. It was the largest and most completely-equipped party that had ever left the base camp. Everything looked propitious at last.
But as soon as they got on the glacier, their troubles began. In spite of one previous day of sunshine since the last storm they found the snow had not melted and hardened as usual, but was still soft and powdery—regular winter conditions—which made slow difficult climbing. The coolies were going very badly. The crevasses had opened so widely and numerously during the summer that the route had been gradually pushed over under the dangerous great north face of Nanga Parbat. They were a long time crossing this avalanche-threatened area, and had barely reached safety on the steep slopes beyond, when the largest avalanche seen during the summer poured down into the basin, sweeping away for hundreds of feet the tracks they had just made. Their progress to Camp II in the deep, soft snow was slow, and they arrived exhausted. Next morning, after a sleepless night, they pressed on to Camp III. They found on the steep slopes that the snow was still like winter powder, and slipped so under foot that it was often necessary to clear it away and cut steps in the hard ice beneath, and the coolie between Herron and Wiessner, who alternated leading, sometimes had to be actually pulled up on the rope. It took them seven hours to get to Camp III, usually a trip of three or four hours. Between fatigue, and the excitement of being at last on the way, they passed at Camp III a second sleepless night.
As they went higher, they found snow conditions growing continually worse. Camp IV, usually an easy stroll of an hour and a half to two hours, was reached only in five hours. Camp IV was completely snowed under, so that it took an hour and a half to dig out the ice cave kitchen even far enough to locate the stove.
Next day was a well-earned day of rest. There was still hope. In the morning the coolies were in good condition, and the weather was still clear. But by evening clouds had gathered all around the horizon, and nine of the twelve coolies came to report themselves too sick to go on. The other three announced that they were tired of the mountain, and also refused to go farther.
During the night it started snowing, and continued all the next day. The men said that they had never seen snow accumulate so fast. In a previous eight-day storm, less had fallen than came in this one night and day. They said it was almost uncanny, it seemed so outside the natural course of things. As it piled up deeper and deeper, all hope vanished, and in the evening they decided finally that they must give up and go down. This meant, among other things, the complete abandonment of the three higher camps, with much valuable equipment, including the three tents, sleeping bags, stoves, provisions, personal belongings, a valuable camera, with some films already exposed, and, most important of all, an altimeter lent by the Meteorological Institute of Prussia. But to recover these things was impossible.
Next morning the men wondered if they would even get down safely. They were plowing now in snow reaching anywhere from their waists to their necks. The coolies, following the three sahibs, who took turns breaking trail, walked in a trench, and if they stepped outside the hardened foot prints, fell and floundered helplessly in the deep softness, until assisted to their feet. The sahibs, as they led, often on the steep slopes started small avalanches, the limited size of which fortunately prevented them burying the men or carrying them into crevasses. There must be frequent stops to take off boots and socks and rub feet, which kept freezing. Between Camps II and I, when, after all the efforts and dangers of the descent, they seemed almost to have reached safety, Wiessner had the narrowest escape of the summer. He was leading along a serac beside a crevasse, when the whole side of the serac fell away from under his feet, and he vanished into the crevasse among a shower of ice blocks and huge icicles. He fell about fifty or sixty feet, and Herron, the second man, was only able to brake him a little toward the end. He was stunned by being hit by some of the ice blocks, but fortunately the largest missed him, and though badly bruised and with a very painful right arm, he cut his way up the crevasse out from under an overhang, to a small shelf above. From there the others were able to help him to the top. After a short rest they went on.
Although the attack had to be abandoned because of the winter conditions, the climbers, even in Camp IV, had decided to make another attempt next year. Merkl must hurry home, but Herron and Wiessner definitely made all arrangements. They talked with the Kashmir government, which seemed very friendly to the suggestion, and we went to Darjeeling to engage Bhotia and Sherpa coolies, as the Hunzas had been found so completely unsatisfactory for high altitude work. Good hopes of success were entertained.
But the situation in Germany and Herron’s unfortunate death on the way home have prevented these plans from being carried out, and the next attack on Nanga Parbat is indefinitely postponed.
1 The photographs illustrating this and the following paper are furnished through the courtesy of various members of the German-American Himalayan Expedition.—Ed.
2 See page 110.
3 During the whole summer our snowshoes were very little used, in spite of the snow conditions, as the slopes proved too steep for their management, although the lighter and handier American ones might have been useful. Skis would have proved practically useless as far as Camp VII, because of the steepness. It is thought, however, that they would have been convenient farther on, if the climbers had reached the more gentle-appearing slopes, near the summit.
4 For detailed reasons for this necessary withdrawal, see Mr. Wiessner’s paper following.